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Open Access

Peer-reviewed

Research Article

High-risk HPV genotypes in Zimbabwean women with cervical cancer: Comparative analyses between HIV-negative and HIV-positive women

  • Oppah Kuguyo,

    Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Writing – original draft, Writing – review & editing

    Affiliations Department of Clinical Pharmacology, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe, Division of Human Genetics, Department of Pathology, Pharmacogenomics and Drug Metabolism Group, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Observatory, Cape Town, South Africa

    ⨯
  • Racheal S. Dube Mandishora,

    Roles Data curation, Formal analysis, Methodology, Visualization, Writing – review & editing

    Affiliations Faculty of Health Sciences, Department of Medical Microbiology Unit, University of Zimbabwe College of Health Sciences, Harare Zimbabwe University of Zimbabwe, Medical Microbiology Unit, Harare, Zimbabwe, Early Detection, Prevention and Infections Branch, International Agency for Research on Cancer, Lyon, France

    ⨯
  • Nicholas Ekow Thomford,

    Roles Formal analysis, Methodology, Software, Supervision, Validation, Writing – review & editing

    Affiliations Division of Human Genetics, Department of Pathology, Pharmacogenomics and Drug Metabolism Group, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Observatory, Cape Town, South Africa, Department of Medical Biochemistry, School of Medical Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, PMB, Ghana

    ⨯
  • Rudo Makunike-Mutasa,

    Roles Data curation, Methodology, Supervision, Writing – review & editing

    Affiliation Department of Pathology, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe

    ⨯
  • Charles F. B. Nhachi,

    Roles Conceptualization, Formal analysis, Resources, Supervision, Writing – review & editing

    Affiliation Department of Clinical Pharmacology, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe

    ⨯
  • Alice Matimba,

    Roles Conceptualization, Data curation, Formal analysis, Funding acquisition, Methodology, Project administration, Resources, Supervision, Writing – review & editing

    Affiliation Advanced Courses and Scientific Conferences, Wellcome Genome Campus, Hinxton, United Kingdom

    ⨯
  • Collet Dandara

    Roles Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – review & editing

    collet.dandara@uct.ac.za

    Affiliation Division of Human Genetics, Department of Pathology, Pharmacogenomics and Drug Metabolism Group, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Observatory, Cape Town, South Africa

    ⨯

Abstract

Background

High-risk human papillomavirus HPV (HR-HPV) modifies cervical cancer risk in people living with HIV, yet African populations are under-represented. We aimed to compare the frequency, multiplicity and consanguinity of HR-HPVs in HIV-negative and HIV-positive Zimbabwean women.

Methods

This was a cross-sectional study consisting of women with histologically confirmed cervical cancer attending Parirenyatwa Group of Hospitals in Harare, Zimbabwe. Information on HIV status was also collected for comparative analysis. Genomic DNA was extracted from 258 formalin fixed paraffin embedded tumour tissue samples, and analysed for 14 HR-HPV genotypes. Data was analysed using Graphpad Prism and STATA.

Results

Forty-five percent of the cohort was HIV-positive, with a median age of 51 (IQR = 42–62) years. HR-HPV positivity was detected in 96% of biospecimens analysed. HPV16 (48%), was the most prevalent genotype, followed by HPV35 (26%), HPV18 (25%), HPV58 (11%) and HPV33 (10%), irrespective of HIV status. One third of the cohort harboured a single HPV infection, and HPV16 (41%), HPV18 (21%) and HPV35 (21%) were the most prevalent. HIV status did not influence the prevalence and rate of multiple HPV infections (p>0.05). We reported significant (p<0.05) consanguinity of HPV16/18 (OR = 0.3; 95% CI = 0.1–0.9), HPV16/33 (OR = 0.3; 95% CI = 0.1–1.0), HPV16/35 (OR = 3.3; 95% CI = 2.0–6.0), HPV35/51 (OR = 6.0; 95%CI = 1.8–15.0); HPV39/51 (OR = 6.4; 95% CI = 1.8–15), HPV31/52 (OR = 6.2; 95% CI = 1.8–15), HPV39/56 (OR = 11 95% CI = 8–12), HPV59/68 (OR = 8.2; 95% CI = 5.3–12.4), HPV66/68 (OR = 7; 95% CI = 2.4–13.5), independent of age and HIV status.

Conclusion

We found that HIV does not influence the frequency, multiplicity and consanguinity of HR-HPV in cervical cancer. For the first time, we report high prevalence of HPV35 among women with confirmed cervical cancer in Zimbabwe, providing additional evidence of HPV diversity in sub-Saharan Africa. The data obtained here probes the need for larger prospective studies to further elucidate HPV diversity and possibility of selective pressure on genotypes.

Citation: Kuguyo O, Dube Mandishora RS, Thomford NE, Makunike-Mutasa R, Nhachi CFB, Matimba A, et al. (2021) High-risk HPV genotypes in Zimbabwean women with cervical cancer: Comparative analyses between HIV-negative and HIV-positive women. PLoS ONE 16(9): e0257324. https://doi.org/10.1371/journal.pone.0257324

Editor: Graciela Andrei, Katholieke Universiteit Leuven Rega Institute for Medical Research, BELGIUM

Received: February 5, 2021; Accepted: August 30, 2021; Published: September 28, 2021

Copyright: © 2021 Kuguyo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: The authors recognise the importance of data sharing in validation, replication and re-analysis, to expand the current body of knowledge and optimise public health. In the current approved ethics protocol for the study, no consent from the study participants was obtained for data sharing. To maintain ethical research practice, the authors will make the data accessible with permission from local ethical review boards, namely the Joint Research Ethics Committee for the University of Zimbabwe College of Health Sciences and The Parirenyatwa Group of Hospitals (citing protocol number: JREC/412/16), as well as Medical Research Council of Zimbabwe (citing reference number: MRCZ/A/2153) on the contact details given below. Seeking ethical approval and engaging the local institutional review boards for re-analysis, validation and replication is important to safeguard the participant information and to ensure governed and harmonised use of this data. Contact details: Postal address: Joint Research Ethics Committee for the University of Zimbabwe College of Health Sciences and The Parirenyatwa Group of Hospitals, Box A178, Avondale, Harare, Zimbabwe. Tel: +2634708140. E-mail: jrec.office@gmail.com or jrec@medsch.uz.ac.zw Postal address: Medical Research Council of Zimbabwe, Cnr Josiah Tongogara/Mazowe Str, Harare, Zimbabwe. Tel: +2634791792 or +2634791193. E-mail: mrcz@mrcz.org.zw.

Funding: The Organisation for Women in Science in the Developing World (OSWD), Medical Research Council of South Africa (SAMRC), the National Research Foundation (NRF) of South Africa and the University of Cape Town provided support in the form of travel funding for OK to conduct work in CD’s research group. No additional external funding was received for this study.

Competing interests: The authors have declared that no competing interests exist.

Introduction

Human papillomavirus (HPV) is a ubiquitous virus, which, under normal physiological conditions can be cleared within 24 months [1,2]. In the presence of favourable physiological and behavioural risk factors, persistent HPV infections lead to carcinogenesis in the cervix and other organs, especially in immunocompromised individuals [3–7]. Numerous HPV genotypes with phylogenetic relatedness have been discovered, yet these genotypes exhibit distinct pathogenic aptitude. High risk HPVs (HR-HPVs) such as 16, 18, 31, 33, 39, 45, 51, 52, 56, 58, 59 and 68 harbour high oncogenic potential, and so, have been influential in the development of HPV prophylactic vaccines [8,9]. The coverage for the HPV prophylactic vaccines is in its infancy in most developing countries, where the coverage is estimated to be more than 12-fold lower than developed countries [10]. As a matter of interest countries such as Zambia, Malawi and Zimbabwe, where the highest global cervical cancer cases are recorded, are still in the pilot and early implementation phases of the national HPV vaccination programs [11,12].

Evidences from diverse global HPV ethnogeography data patterns, for example, shows that HPV51 is predominantly observed in Caucasians, while HPV58 is skewed towards East Asia and Latin America [13–17]. An abundance of data also substantiates that Africa harbours significant heterogeneity between populations, and to be specific, persistent HPV66 is ubiquitous in Northern Africa, while genotypes such as HPV35 and 52 are reportedly abundant in sub-Saharan Africa (SSA) [18–23]. It is thought that the stark dissimilarities of HPV distribution and cervical cancer between SSA and the rest of the world are influenced by HIV co-infection, leading to the classification of cervical cancer as an AIDS-defining condition [5,24–29]. However, emerging data to this effect has been contraindicative. Of great relevance is the unabated cervical cancer burden even after the introduction of anti-retroviral therapies (ART), compared to other HIV-related cancers, that have since dwindled [30–39]. This data suggests other potential competing risk factors, which are yet to be defined.

Despite the strides made to understand the relationship between HPV, HIV and cervical cancer, there is still a gap in SSA. Particularly, in Zimbabwe, most studies have examined HPV in normal cervical cytology and precancerous lesions, leaving only a few studies that focus on cervical tumour tissue [5,7,17,40–43]. High prevalence of genotypes such as HPV16, 18, 31, 33, 45, 56 have been detected in tumour tissue non-synonymously [22,44–46]. There is very little data on the HPV genotype profile for cervical cancer in Zimbabwe. This study aimed to analyse the frequency and multiplicity of HR-HPV genotypes in HIV-negative and HIV-positive Zimbabwean women with histologically confirmed cervical cancer.

Materials and methods

Study design and setting

This was a cross-sectional study consisting of 258 women with histologically confirmed invasive cervical cancer diagnosis. This study recruited participants between July 2016 and January 2019 from an outpatient oncology facility, Parirenyatwa Group of Hospitals Radiotherapy and Chemotherapy Centre (RTC), in Harare, Zimbabwe. The biospecimens for analysis were collected at the pathology laboratory of diagnosis, namely Lancet Pathology and Parirenyatwa Group of Hospitals Pathology Department. Collected samples were processed as Formalin fixed paraffin embedded (FFPE) blocks.

Ethical approval

All human health research was in accordance with the Helsinki declaration. Ethical approval was obtained from University of Zimbabwe College of Health Sciences and Parirenyatwa Group of Hospitals Joint Research Ethics Committee (412/16), Medical Research Council of Zimbabwe (A/2153), University of Cape Town Research Ethics Committee and Research Council of Zimbabwe (No: 03351).

Study participants

The participants from the current study were nested in a pharmacogenomics of cervical cancer study, aiming to recruit women who were newly diagnosed with cervical cancer, and were eligible to receive radical therapy. Potential study participants were identified through the RTC hospital registry. To be considered eligible for this study, women had to be ≥18 years, with histologically confirmed diagnoses of invasive cervical cancer staged between 1b – 4A, and were earmarked for curative anti-cancer therapy. Individuals who were diagnosed with resectable (stage 1A) disease that did not require chemo/radio- therapies or advanced disease that required palliative care (stage 4B) were excluded from the study, because these individuals were referred for care outside of the RTC. Eligible participants were informed of the study verbally, and the women willing to enroll provided written consent. To maintain participant confidentiality, all participant data was de-identified and assigned study numbers. The clinical and demographic information for all recruited participants were abstracted onto a case report form. Demographic information such as age, residency, histopathological tumour characteristics, were collected from the patient folder in the RTC. In addition, behavioral, lifestyle factors and sexual history were collected by interviewing the study participants, namely history of alcohol, smoking, parity, age at sexual debut, number of sexual partners, history of circumcised partner, sexually transmitted infections were also collected. Data on HIV status was also collected for comparative analysis.

DNA extraction and HPV genotyping

A total of 5mg of the FFPE blocks were sectioned off in preparation for genetic analysis. Genomic DNA was isolated from the FFPE scrolls following a slightly modified manufacturers’ protocol from Zymo genomic DNA extraction FFPE kit (Zymo Research, California, USA). Paraffin was removed by adding a Xylene-based deparaffinization solution and incubating at 55°C for 30 minutes. The wax layer was then aspirated and the remaining biopsy tissue was digested overnight using 10mg/ml Proteinase K (Zymo Research, California, USA). The quantity and quality of DNA was assessed using a Nanodrop™ Spectrophotometer 2000/2000c (Nano-drop™, ThermoFisher, Denver, USA) and DNA integrity was evaluated by running a 1% agarose gel electrophoresis. The extracted DNA was stored at -80°C for further analysis.

Genotyping for high-risk HPV subtypes was undertaken using clinically validated Anyplex™ II HPV HR detection kit (Seegene, Seoul, South Korea). The Anyplex™ II HPV HR detection kit (Seegene, Seoul, South Korea) targets the HPV L1 gene (encoding the capsid) using primers provided in the Anyplex kit. This assay uses Dual Priming Oligonucleotides (DPO™) and tagging oligonucleotide cleavage and extension (TOCE™) technology which enables the distinguishing of 14 HR-HPVs in a single reaction, namely, HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68. A total reaction of 20μl was used during genotyping, following the manufacturers’ protocol. Each reaction contained a human β-globin internal control, L1 primers, oligonucleotides and enzymes. A negative control, as well as 3 positive controls (DNA mixture of pathogen clones) were run concurrently with each test plate to confirm the validity of the amplification. The CFX96™ real-time thermocycler (Bio-Rad, Applied Biosystems, California, USA) was used under thermocycling conditions recommended in the Seegene protocol. Fluorescence was detected using the end point cyclic melting temperature analysis. Seegene Viewer v2.0 program (Seegene, Seoul, South Korea) was used to analyse and interpret fluorescence data. Each result was considered valid when the internal control was detected in the sample (IC+). Positive result (+) indicated HPV DNA presence, while negative result (-) indicated the absence of the viral DNA. All HPV negative results with a positive endogen internal control (IC+) were not re-analysed.

HPV genotype frequency data mining

Data on the HPV genotypes of African populations was extracted from the HPV Information Centre database [47]. The HPV Information Centre consolidates data from published literature and official reports published by the World Health Organisation, United Nations, The World Bank, International Agency for Research on Cancer’s Globocan and Cancer Incidence in Five Continents. We filtered the report for data on the African continent, and collected the data on the most frequently detected HPV genotypes in women with confirmed cervical cancer.

Statistical and data analysis

STATA v12.0 (StataCorp LLC, Station College, TX, USA) and Graphpad v8 (Prisma, San Diego, California) statistical software packages were used for data analysis. Demographic and clinical data were allocated into either continuous data or categorical data. Continuous data were expressed as mean ± standard deviation or median (inter-quartile range), while the categorical data was expressed as absolute or relative frequencies. For the comparison of the sociodemographic factors between HIV negative and HIV positive study participants, the two-sample Wilcoxon rank-sum test and Chi-squared test of independence was used. Correlation between the various HPV genotypes and HIV status was performed using Poisson’s and Logistic regression. The Chi-squared test of homogeneity was used to compare the frequency of HPV genotypes among African women using Fisher’s exact and Chi-squared values as test statistics. Univariate regression was used to determine an association between the established HPV risk factors with the HR-HPV genotype infections. Multivariate logistic regression was used to determine an association between the pairings of the HPV genotypes using age, and HIV status as predictors for the model. Further sensitivity analyses were performed for the co-segregating HPV genotypes, using multivariate regression models, and controlling for known HPV risk factors, namely, age, history of STI, parity, HIV status, age of sexual debut and tumour histology. We considered p<0.05 as statistically significant. For analysis, all individual HPV genotypes regardless of whether they occur as single or multiple infections were analysed and reported as standalone genotypes. None of the statistical analysis took into account the species from which the HPV genotypes are from.

Results

Sociodemographic features of the study participants

Sociodemographic and clinical characteristics of the study group are summarized in Table 1. Of the 258 cervical cancer patients recruited for this study, 45% (n = 116) were confirmed HIV positive. The median age (inter-quartile range) of the participants was 51 years (42–62). The overall median for age was significantly different (p = 0.001) between the HIV-positive and HIV-negative cervical cancer groups. Further analysis of the age frequency distribution showed that in HIV positive women, age was skewed to the younger women (<50 years) compared to women with HIV-negative status (Fig 1). Most of the sociodemographic risk factors were comparable between the groups, however, the behavioural risk factors, such as number of sexual partners (p = 0.001) and history of sexually transmitted infections (p = 0.010) differed between the HIV-negative and HIV-positive groups. In univariate regression analysis, none of the HPV-related risk factors (i.e., age, sexual debut, parity and STI history) were found to be significantly associated with any of the HR-HPV genotypes or multiple HR-HPV genotype infections (S1 Table).

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Fig 1. Age distribution of study cohort stratified by HIV status (n = 258).

https://doi.org/10.1371/journal.pone.0257324.g001

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Table 1. Sociodemographic and behavioural characteristics of the study participants.

https://doi.org/10.1371/journal.pone.0257324.t001

HPV genotype prevalence

The 258 cervical cancer patients were screened for HR-HPV DNA, and 96% (n = 248) were positive, representing 14 HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68) (Table 2) There was no difference in HPV positivity and HPV type between the HIV negative and positive groups. Distribution of HPV in this cohort stratified by HIV status is illustrated in Table 2. HPV16 was the most prevalent genotype detected in 48% (n = 123) of the participants, with high frequencies for the following genotypes; HPV35 (26.4%), HPV18 (25.2%), HPV58 (10.5%), HPV33 (9.7%), and HPV31 (6.6%).

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Table 2. HR-HPV genotypes by HIV status (n = 258) and the HPV phylogenetic classification.

https://doi.org/10.1371/journal.pone.0257324.t002

HPV mono-infections

About one-third (n = 85) of the study cohort were harbouring a single HR-HPV infection. The prevalence and distribution of HR-HPV mono infections is illustrated in Fig 2. In this group of women with confirmed cervical cancer, the most commonly reported mono-infections were HPV16 (41%), HPV18 (21%) and HPV35 (21%). This study did not observe any HPV mono-infections arising from HPV genotypes 56, 59 and 66. Comparative analysis between HIV-negative and HIV-positive women showed that there were no statistically significant differences in the prevalence HR-HPV mono-infections (p = 0.400).

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Fig 2. The HPV mono infection distribution in women with confirmed cervical cancer (n = 85).

https://doi.org/10.1371/journal.pone.0257324.g002

Multiple HR-HPV infections

Majority (67%) of the cohort exhibited multiple HPV infections. Of the 14 HR-HPV genotypes analysed in this study, 63% (n = 163) harboured multiple (>2) HPV genotypes (Table 3). Fifty nine percent of the study participants exhibited infection with 2 HR-HPVs, while 19% were infected with 3 HR-HPVs. The most common multiple infections included HPV16 and 35 (21%), followed by HPV16/18 and HPV16/58. The highest number of multiple HPV serovariants per individual reported was 6, in 3.7% of study subjects (Table 3). There was no difference in the number of multiple infections between HIV positive and HIV negative cervical cancer patients. Distribution of multiple HPV genotypes stratified by HIV status are illustrated in S2 Table.

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Table 3. Multiple HR-HPV infections, stratified by HIV status (n = 163).

https://doi.org/10.1371/journal.pone.0257324.t003

Furthermore, the incidence of multiple-type HPV infections was assessed to determine if specific HPV genotypes tend to co-segregate, or if the multiple-type infections occur as a result of chance. HIV status was not a significant contributor to the co-segregation patterns. We used multivariate logistic regression, using the HPV genotypes as predictors, while controlling for age and HIV status, as illustrated below (Fig 3). We detected statistically significant associations (p<0.05) between HPV16 and 33 (OR = 0.3; 95% CI = 0.1–1.0), HPV16 and 35 (OR = 3.3; 95% CI = 2.0–6.0), HPV16 and 18 (OR = 0.3 95% CI = 0.1–0.9), HPV35 and 51 (OR = 6.0; 95%CI = 1.8–15.0), HPV39 and 51 (OR = 6.4; 95% CI = 1.8–15), HPV31 and 52 (OR = 6.2; 95% CI = 1.8–15), HPV39 and 56 (OR = 11 95% CI = 8–12), HPV59 and 68 (OR = 8.2; 95% CI = 5.3–12.4), and HPV66 with 68 (OR = 7; 95% CI = 2.4–13.5). The respective odds ratios and 95% confidence intervals for all significant HPV genotypes are shown in Fig 4. In order to ensure that lack of significance observed was not a result of low study power, a sensitivity appraisal was conducted, using multivariate regression analyses controlling for age, history of sexually transmitted infections, parity, HIV status, age at sexual debut and tumour histology. In this sensitivity analyses, all the co-segregation patterns remained statistically significant except HPV16/33 (OR = 0.4; 95% CI = 0.2–1.9; p = 0.05), HPV35/52 (OR = 0.5; 95% CI = 0.1–4.3; p = 0.50) (S3 Table).

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Fig 3. Heatmap of co-segregation of any two HPV types among Zimbabweans.

https://doi.org/10.1371/journal.pone.0257324.g003

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Fig 4. Odds ratios and 95% confidence intervals (95% CI) for co-occurrence of high-risk HPV infections among Zimbabweans.

* Indicates co-segregation of HPV genotypes in the same phylogenetic clades.

https://doi.org/10.1371/journal.pone.0257324.g004

Comparing the distribution of different HPV types in women from populations across Africa

The prevalence of the various HPV genotypes in the Zimbabwean study cohort was compared to the most common HPV genotypes on other African women across the continent, using data obtained from HPV Information Centre database [47] and summarized into Table 4. In comparison to the rest of the African continent data, our study reported significantly higher HPV35 (p<0.001), HPV51 (p = 0.043), HPV58 (p = 0.010) and HPV39 (p = 0.043). Across the different African regions, most of the HPV genotypes were comparable (p>0.05), and HPV16 was the most prevalent genotype. However, in North Africa (p = 0.047), the frequency of HPV16 is significantly higher, while HPV45 (p = 0.011) and HPV59 (p = 0.005) are significantly higher in West Africa compared to the other African regions. Additionally, the HPV information centre database also showed that HPV26 was one of the top 10 genotypes detected in cervical cancer tissue in Southerrn Africa, and HPV53 in Northern and Southern Africa.

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Table 4. Comparison of the frequencies of the most common HPV genotypes reported across Africa.

https://doi.org/10.1371/journal.pone.0257324.t004

Discussion

There is a plethora of studies that have analyzed HPV genotyping profiles in different populations across the globe, and what is apparent is that HPV16 and 18 are highly prevalent in cervical cancer. The global HPV prevalence reports HPV16 (55%) as the highest followed by HPV18 (14%), which is supported by our data, with 48% and 25%, respectively. However, in stark contrast to the global data, we report here a >13-fold higher frequency (26%) of HPV35 among Zimbabwean women with cervical cancer, compared to Caucasians (~2%) and Asian (~1%) cervical cancer patients [48,49]. Across the African continent, there is heterogeneity in the frequency of HPV35, ranging from as low as 6% in South Africa, Burkina Faso (9%), Nigeria (9%), Tanzania (15%), Mozambique (17%), and up to the comparable 24% observed among Malawian women [18,28,50–58]. It is important to note, an earlier study among Zimbabwean women [22] which showed a frequency of 11% for HPV35. This discrepancy could be parenthetic to methodological differences in HPV genotyping. Specifically, our study utilised the multiplex PCR method, while Mudini et al. used PGMY09/11 PCR and dot plot hybridization. Although both methods yield highly concordant findings, the PGMY09/11 HPV detection method has been associated with a higher rate of false negatives compared multiplex PCR [59–61].

Moreover, a high HPV genotype frequency in the general population is not an adequate proxy for carcinogenic potential. For example, in Latin America, HPV35 is as ubiquitous as in SSA, but is widespread in precancerous lesions and not in cancer [62]. Novel genetic variations in the coding and non-coding regions of HPV35 have been discovered, especially in African women, and women of African ancestry, which are not present in Caucasian, Asian and Hispanic populations [23,63]. These genetic polymorphisms are thought to account for the distinct HPV35 virulence and oncogenic potential observed in Africans, versus Latin America. However, not much whole HPV35 sequencing has been reported on African cervical tumour samples, thus, there is a potential to discover even more variants in different African populations.

While it has been previously thought that HPV16 and a few other genotypes exhibited higher innate potential to evade the host immune system, and other genotypes required a suppressed immune system to flourish e.g. HPV35 [64,65], new data seem to show that infection with HPV35 can also be correlated with persistence and unresolvable precancerous lesions [13,23,28,53,66–68]. For example, and contrary to earlier expectations, studies from SSA show that HPV35 is one of the most ubiquitious genotypes, irrespective of HIV status, further confirming our observation in the present study [19,20,22,57,69]. Our observations agree with reports from other studies evaluating HPV prevalence, distribution and multiplicity in Zimbabwean women, notwithstanding cervical cytology status [22,63]. It is equally vital to include in the equation immune reconstitution resulting from increased access to ART in Zimbabwe, which could be contributing to the homogeneity of the HPV genotype distribution and observed multiplicity in our study, and other Zimbabwean studies.

Surprisingly, the introduction of ART has not been met with sizeable decline of cervical cancer, compared to other HIV-related malignancies such as Kaposi’s Sarcoma and Non-Hodgkins’ Lymphoma, which are now rarely detected [70,71]. To ascertain the role of immune reconstitution in HPV persistence and cervical cancer, immunological factors (which were not evaluated in the current study) such as HIV viral load, HPV viral load, CD4+ count and duration of ART need to be investigated [53,72]. There is, however, evidence in other African populations to suggest that only a small fraction of women with HIV/HPV are likely to develop invasive cervical cancer without influence from CD4+ count, thus pointing to an increased role of the other competing risk factors and the need to interrogate them as potential HPV persistence drivers, including host genetics [73–82].

Persistence of HPV and the presence of multiple HPV infections are both phenomena closely correlated with HIV-induced immunosuppression [83–88]. Additionally, other sexual behavioural characteristics such as history of STIs, higher number of sexual partners are also key contributors for HPV multiplicity [89–91]. Although our study reports high multiple HPV infection rate, we found no relationship between sexual behavioral factors such as HIV and STI history, and risk of harbouring multiple HPV genotypes. Not many studies have sought to understand the patterns by which multiple HPV genotypes co-segregate and interact to induce carcinogenesis. Some studies highlight that multiple infections occur as random events, while other studies allude to competitive or co-operative consanguinity of specific HPV genotypes [59,92–94]. Aggregation of HPV genotypes with phylogenetic relatedness has been observed at different degrees, and HPV 16, 18, 58 and 66 have been shown to occur mostly as single infections, in Americans and Latin Americans, while HPV35 and 45 were more likely to present as multiple infections [59,92–94]. On the contrary, our study reports no statistically significant differences in the HPV genotype distribution for single and multiple infections for any of the HPV genotypes. Furthermore, we report type-specific HPV clustering of genotypes from the same phylogenetic clades, namely, HPV16/33 and HPV16/35; while the rest of the co-segregation we reported here was of genotypes that are of diverse phylogenetic clades. Previous data suggests that multiple infection with genotypes of diverse HPV phylogenetic clades is directly correlated with no history of the HPV prophylactic vaccine, ascribed to the punitive host induced cross-protection, compared to the vaccine induced response [59,92,95–98]. In Zimbabwe, the HPV vaccination program is still in early implementation phase, therefore, most women at reproductive ages and above are reliant on host immunology prevention. This is similar in most of Africa, where there is limited access and coverage of the HPV vaccine, even though the burden of cervical cancer is disproportionately high here, and the populations are exposed to other dissonant evolutionary selective pressures which collectively exacerbate the risk of HPV persistence [99,100].

Analysis of the HPV genotypes detected across Africa, by region confirms distinct HPV ethnogeographical patterns. Of great interest is the probable high-risk genotype, HPV26, which was observed only in cervical cancer tissue from Southern Africa. Because HPV26 is not a definitive HR-HPV, it is often overlooked, so its burden in Africa may be under-reported, and consequently its contribution to cervical cancer. HPV51, HPV56 and HPV59 were seemingly exclusively observed in East and West African women. It is important to note that these genotypes are not covered by current HPV vaccines. As of 01 August, 2021, the most robust vaccine, Gardasil-9, targets HPV 6, 11, 16, 18, 31, 33, 45, 52 and 58, for which the estimated cross-protective potential translates to cloistering <70% of HPV-related cancers [8,101–103]. Even so, longitudinal data illustrates diminished cross-protective immunogenicity and reactogenicity over time, leaving some ethnogeographical groups exposed and susceptible to HPV infection [23,53,54,104–107]. Given the significant HPV diversity, and the genetic variation in Africa it may be of great benefit to conduct large-scale, longitudinal HPV genotyping studies in women from different African countries, such as the African Collaborative Center for Microbiome and Genomics Research (ACCME) study in Nigeria [107] so as to understand the impact of HPV, HIV and related host genetic factors for potential utility as biomarkers for cervical cancer in Africa. This large-scale empirical data would be key to determine which genotypes characteristically resolve, or progress to cervical cancer along with HIV in African settings and are fundamental towards developing a comprehensive and Africa-specific HPV vaccine.

Additionally, no HR-HPV infection detected in about 4% of the cohort irrespective of HIV status. This could have resulted from the fact that this particular sub-group were harbouring an HPV subtype that was not characterised by the assay kit used in this study. For example, HPV6 and 11 are established to play a causative role in genital warts, or HPV26 which we found in the comparative analysis to be idiosyncratic to Southern Africa [17,108]. Future studies should characterise for HPV using broader spectrum kits, simultaneously detecting low- and high- risk HPV subtypes. It is also possible that this group harbours HPV-negative cervical tumours, which are known to be quite rare and occurring in <5% of cases. A previous study conducted by Kjetland and collaborators (2010) reported schistosomiasis-induced squamous intraepithelial neoplasia with no HPV on Zimbabwean women [109].

In conclusion, our study analysed HR-HPV sub-types in Zimbabwean women, and presents data which will add to HPV diversity in SSA. This study is the first to describe high frequency of HPV35, comparable to other HR-HPVs such as HPV18 in Zimbabwean women with cervical cancer. Furthermore, this study is also the first to report multiple type-specific HPV subtypes in African populations, providing empirical evidence of high consanguinity of HR-HPV genotypes despite HIV status. The data obtained here is fundamental towards determining the efficacy of the commercially available prophylactic vaccines in SSA populations that harbour disparate viral genome profiles and are subject to evolutionary pressures.

Supporting information

S1 Table. Risk factors of HPV in association with the various HPV genotypes.

https://doi.org/10.1371/journal.pone.0257324.s001

(PDF)

S2 Table. The number of individuals harbouring specific HPV genotypes stratified by HIV status.

https://doi.org/10.1371/journal.pone.0257324.s002

(PDF)

S3 Table. Sensitivity analysis for HPV co-segregation.

https://doi.org/10.1371/journal.pone.0257324.s003

(PDF)

Acknowledgments

The authors wish to acknowledge Gamuchirai Rinashe and Frances Desales Misi who played an instrumental role in data collection and specimen retrieval.

References

  1. 1. Adebamowo SN, Dareng E, Famooto A, Odutola KM, Bakare R, Adebamowo CA, et al. Cohort profile: African Collaborative Center for Microbiome and Genomics Research (ACCME). J Glob Oncol. 2016 Nov 10;2(3):65.
  2. 2. Bosch FX, Broker TR, Forman D, Moscicki AB, Gillison ML, Doorbar J, et al. Comprehensive control of Human papillomavirus infections and related diseases. Vaccine. 2013;31(8): 1–13.
  3. 3. Bansal A, Signh MP, Rai B. Human papillomavirus-associated cancers: A growing global problem. International Journal of Applied and Basic Medical Research. 2016;6(2): 84–89. pmid:27127735
  4. 4. Choi YJ, Park JS. Clinical significance of human papilloma virus genotyping. Journal of Gynecologic Oncology. 2016;27(2): e21. pmid:26768784
  5. 5. Baay MF, Kjetland EF, Ndhlovu PD, Deschoolneester V, Mduluza T, Gomo E, et al. Human papillomavirus in a rural community in Zimbabwe: The impact of HIV co-infection on HPV genotype distribution. Journal of Medical Virology. 2004;73(3). pmid:15170646
  6. 6. Giuliano AR, Botha MH, Zeier M, Abrahamsen ME, Glasshoff RH, Van der Laan LE, et al. High HIV, HPV, STI prevalence among young Western Cape, South African women: EVRI HIV prevention preparedness trial. J Acquir Immune Defic Syndr. 2015; 68(2): 227–235. pmid:25415290
  7. 7. Marembo T, Mandishora RD, Borok M. Use of multiplex polymerase chain reaction for detection of high-risk human papillomavirus genotypes in women attending routine cervical cancer screening in Harare. Intervirology. 2019;62(2): 90–95. pmid:31412350
  8. 8. Boda D, Docea AO, Calina D, Illie MA, Caruntu C, Zurac S, et al. Human papillomavirus: Apprehending the link with carcinogenesis and unveiling new research avenues. Int J Oncol. 2018;52(3): 637–655. pmid:29393378
  9. 9. Kuguyo O, Tsikai N, Thomford NE, Magwali T, Madziyire MG, Nhachi CFB, et al. Genetic susceptibility for cervical cancer in African populations: what are the host genetic drivers? OMICS: A journal of integrative Biology. 2018;22(7): 468–482. pmid:30004844
  10. 10. Bruni L, Diaz M, Barrionuevo-Rosas L, Herrero R, Bray F, Bosch FX, et al. Global estimates of human papillomavirus vaccination coverage by region and income level: a pooled analysis. Lancet Glob Health. 2016;4:e453–63. pmid:27340003
  11. 11. Zimbabwe Ministry Of Health and Child Care. Lessons learned: HPV vaccine nationwide introduction in Zimbabwe. 2018.[Cited 2021 Mar 24]. https://publications.jsi.com/JSIInternet/Inc/Common/_download_pub.cfm?id=21927&lid=3.
    • 12. Path Project. Global HPV Vaccine Introduction Overvie: Projected and current national introductions, demonstration/pilot projects, gender-neutral vaccination programs, and global HPV vaccine introduction maps (2006–2023). Updated May 4 2020.
      • 13. de Sanjose S, Quint WG, Alemany L, Geraets DT, Klaustermeier JE, Lloveras B, et al. Human papillomavirus genotype attribution in invasive cervical cancer: a retrospective cross-sectional worldwide study. Lancet Oncol. 2010;11(11): 1048–56. pmid:20952254
      • 14. Chan PKS, Zhang C, Park JS, Smith-McCune KKS, Palefsky JM, Giovannelli L, et al. Geographical distribution and oncogenic risk association of human papillomavirus type 58 E6 and E7 sequence variations. Int J Cancer. 2013;132(11): 2528–36. pmid:23136059
      • 15. Basto DL, Vidal JP, Pontes VB, Felix SP, Pinto LC, Soares BM, et al. Genetic diversity of human papillomavirus types 35, 45 and 58 in cervical cancer in Brazil. Arch Virol. 2017;162(9): 2855–2860. pmid:28597068
      • 16. Bruni L, Albero G, Serrano B, Mena M, Gomez D, Munoz J, et al. ICO/IARC Information Centre on HPV and Cancer. Human Papillomavirus and related diseases in the world. Summary Report 17 June 2019. 2019a [Cited 2020 Jul 9]. https://www.hpvcentre.net/statistics/reports/XWX.pdf?t=1594289065430.
        • 17. Bruni L, Albero G, Serrano B, Mena M, Gomez D, Munoz J, et al. ICO/IARC Information Centre on HPV and Cancer. Human Papillomavirus and related diseases in Africa. Summary Report 17 June 2019. 2019b. [Cited 2020 Jul 9]. https://www.hpvcentre.net/statistics/reports/XFX.pdf?t=1594292863080.
          • 18. Munoz N, Bosch FX, de SanJose S, Herrero R, Castellsague X, Shah KV, et al. Epidemiologic classification of human papillomavirus types associated with cervical cancer. N Engl J Med. 2003;348: 518–527. pmid:12571259
          • 19. Castellsague X, Menendez C, Loscertales MP, Kornegay JR, dos Santos F, Gomez-Olive FX, et al. (2001) Human papillomavirus genotypes in rural Mozambique. Lancet. 2001;358(9291):1429–30. pmid:11705494
          • 20. Naucler P, da Costa FM, Ljungberg O, Bugalho A, Dillner J. Human papillomavirus genotypes in cervical cancers in Mozambique. Journal of General Virology. 2004;85: 2189–2190. pmid:15269357
          • 21. Clifford G, Franceschi S, Diaz N, Munoz N, Villa LL. HPV type distribution in women with and without cervical neoplastic diseases. Vaccine. 2006;24(3): 26–34. pmid:16950015
          • 22. Mudini W, Palefsky JM, Hale MJ, Chirenje MZ, Makunike-Mutasa R, Mutisi F, et al. Human papillomavirus genotypes in invasive cervical carcinoma in HIV seropositive and seronegative women in Zimbabwe. J Acquire Immune Defic Syndr. 2019;79(1): e1–e6.
          • 23. Pinheiro M, Gage JC, Clifford GM, Demarco M, Cheung LC, Chen Z, et al. Association of HPV35 with cervical carcinogenesis among women of African ancestry: Evidence of viral host interaction with implications for disease intervention. Int J Cancer: Cancer Epidemiology. 2020;147(10): 2677–2686. pmid:32363580
          • 24. Chaturvedi AK, Dumestre J, Gaffga AM, Mire KM, Clark RA, Braly PS, et al. Prevalence of human papillomavirus genotypes in women from three clinical settings. J Med Virol. 2005;75(1):105–13. pmid:15543579
          • 25. Singh DK, Anastos K, Hoover DR, Burk RD, Shi Q, Ngendahayo L, et al. Human papillomavirus infection and cervical cytology in HIV-infected and HIV-uninfected Rwandan women. J Infect Dis. 2009;199(12): 1851–61. pmid:19435429
          • 26. Veldhuijzen NJ, Braunstein SL, Vyankandondera J, Ingabire C, Ntirushwa J, Kestelyn E, et al. The epidemiology of human papillomavirus infection in HIV-positive and HIV-negative high-risk women in Kigali, Rwanda. BMC Infect Dis. 2011;11:333. pmid:22136570
          • 27. McDonald AC, Tergas AI, Kuhn L, Denny L, Wright TC Jr. Distribution of human papillomavirus genotypes among HIV-positive and HIV-negative women in Cape Town, South Africa. Front Oncol. 2014; 4:48. pmid:24672770
          • 28. Akaloro-Anthony SN, Al-Mujtaba M, Famooto AO, Dareng EO, Olaniyan OB, Offiong R, et al. HIV associated high risk HPV infection among Nigerian women. BMC Infect Dise. 2013;13: 521. pmid:24192311
          • 29. Adebamowo SN, Olawande O, Famooto A, Dareng EO, Offiong R, Adebamowo CA, et al. Persistent low-risk and high-risk human papillomavirus infections of the uterine cervix in HIV-negative and HIV-positive women. Front Public Health. 2017a;5(178): 1–11.
          • 30. Kahesa C, Mwaiselage J, Wabinga HR, Ngoma T, Kalyango JN, Karamagi CA. Association between invasive cancer of the cervix and HIV-1 infection in Tanzania: the need for dual screening. BMC Public Health. 2008;8: 262. pmid:18664298
          • 31. Cheung MC, Pantanowitz L, Dezube BJ. AIDS-related malignancies: emerging challenges in the era of highly active antiretroviral therapy. Oncologist. 2015;10: 412–426. pmid:15967835
          • 32. Echimane AK, Ahnoux AA, Adoubi I, Hien S, M’Bra K, D’Horpock A, et al. Cancer incidence in Abidjan, Ivory Coast: results from the cancer registry, 1995–1997. Cancer. 2000;89: 653–663. pmid:10931466
          • 33. Asamoah-Odei E, Asiimwe-Okiror G, Garcia Calleja JM, Boerma JT. Recent trends in HIV prevalence among pregnant women in sub-Saharan Africa. AIDScience. 2003;3(19): 1–8.
          • 34. Sasco AJ, Jaquet A, Boidin E, Ekouevi DK, Thouillot F, Lemabec , et al. (2010) The challenge of AIDS-related malignancies in Sub-Saharan Africa. PLOS ONE. 2010;5(1): e8621. pmid:20066157
          • 35. Shiels MS, Pfieffer RM, Gail MH, Hall HI, Li J, Chaturvedi AK, et al. Cancer burden in the HIV-infected population in the United States. J Natl Cancer Inst. 2011;103: 753–62. pmid:21483021
          • 36. Mwakigonja AR, Torres LMM, Mwakyoma HA, Kaaya EE. Cervical cytological changes in HIV-infected patients attending care and treatment clinic at Muhimbili National Hospital, Dar es Salaam, Tanzania. Infect Agent Cancer. 2012;7(3). pmid:22335893
          • 37. Adler DH, Wallace M, Bennie T, Mrubata M, Abar B, Meiring TL, et al. Cervical dysplasia and high-risk papillomavirus infections among HIV-infected and HIV-uninfected adolescent females in South Africa. Infect Dise Obstet Gynecol. 2014: 498048. pmid:25389377
          • 38. Chambuso RS, Kaambo E, Stephan S. Observed age difference and clinical characteristics of invasive cervical cancer patients in Tanzania: A comparison between HIV-positive and HIV-negative women. Journal of Neoplasm. 2017;2(3):16.
          • 39. Dhokotera T, Bohlius J, Spoerri A, Egger M, Ncayiyana J, Olago V, et al. The burden of cancers associated with HIV in the South African public health sector, 2004–2014: a record linkage study. Infectious Agents and Cancer. 2019;14(12). pmid:31073325
          • 40. Clayden P, HIV i-Base. HPV genotypes in HIV-positive women in Zimbabwe and Uganda. 2008. [Cited on 2020 Jul 9]. http://i-base.info/htb-south/46.
            • 41. Smith-McCune KK, Shiboski S, Chirenje MZ, Magure T, Tuveson J, Ma Y, et al. Type-specific cervico-vaginal human papillomavirus infection increases risk of HIV acquisition independent of other sexually transmitted infections. PLoS One. 2010;5(4): e10094. pmid:20386706
            • 42. Matuvhunye T, Dube-Mandishora RS, Chin’ombe N, Chakafana G, Mbanga J, Zumbika E, et al. Genotyping Human Papillomavirus in Women Attending Cervical Cancer Screening Clinic in Harare, Zimbabwe. Br Microbiol Res J. 2016;16(6): 1–9.
            • 43. Dube-Mandishora RS, Christiansen IK, Chinombe N, Duri K, Ngara B, Rounge TB. Genotypic diversity of anogenital human papillomavirus in women attending cervical cancer screening in Harare, Zimbabwe. J Med Virol. 2017;89(9): 1671–7. pmid:28390142
            • 44. Chirara M, Stanczuk GA, Tswana SA, Nystrom L, Bergstrom S, Moyo SR, et al. Low risk and high risk human papilloma viruses (HPVs) and cervical cancer in Zimbabwe: epidemiological evidence. Centr Afr J Med. 2001;47(2): 32–5.
            • 45. Stanczuck GA, Kay P, Sibanda E, Allan B, Chirara B, Tswana SA, et al. Typing of human papillomavirus in Zimbabwean patients with invasive cancer of the uterine cervix. Obstet Gynecol Scand. 2003a;82(8): 762–6.
            • 46. Stanczuck GA, Kay P, Allan B, Chirara M, Tswana SA, Bergstrom S, et al. Detection of human papillomavirus in urine and cervical swabs from patients with invasive cervical cancer. J Med Virol. 2003b;71(1): 110–4.
            • 47. HPV Information Centre. HPV Data Statistics. 2020. [Cited 2020 October 2]. https://www.hpvcentre.net/datastatistics.php.
              • 48. Sebbelov AM, Davidson M, Kjaer SK, Jensen H, Gregoire L, Hawkins I, et al. Comparison of human papillomavirus genotypes in archival cervical cancer specimens from Alaska natives, Greenland natives and Danish Caucasians. Microbes and Infection. 2000;2(2): 121–126. pmid:10742684
              • 49. Chan CK, Aimagambetova G, Ukybassova T, Kongrtay K, Azizan A. Human papillomavirus infection and cervical cancer: epidemiology, screening, and vaccination- review of current perspectives. J Oncol. 2019;3257939. pmid:31687023
              • 50. Bhatla N, Lai N, Bao YP, Ng T, Qiao YL. A meta-analysis of human papillomavirus type-distribution in high-grade cervical lesions in women from South Asia: Implications for vaccinations. Vaccine. 2008; 26(23): 2811–2817. pmid:18450340
              • 51. Castellsague X. Natural history and epidemiology of HPV infection and cervical cancer. Gynecol. Oncol. 2008;110(3)2: S4–7. pmid:18760711
              • 52. Didelot-Rousseau M, Nagot N, Costes-Martineau V, Valles X, Ouedrago A, Konate I, et al. Human papillomavirus genotype distribution and cervical squamous intraepithelial lesions among high-risk women with and without HIV-1 infection in Burkina Faso. Br J Cancer. 2006; 95, 355–362. pmid:16832413
              • 53. Denny L. Adewole I, Anorlu R, Dreyer G, Moodley M, Smith T, et al. Human papillomavirus prevalence and type distribution in invasive cervical cancer in sub-Saharan Africa. Int J Cancer. 2014;134(6):1389–98. pmid:23929250
              • 54. Ali-Risasi C, Verdonck K, Padalko E, Broeck DV, Praet M. Prevalence and risk factors for cancer of the uterine cervix among women living in Kinshasa, the Democratic Republic of the Congo: A cross sectional study. Infect Agent Cancer. 2015;10(20). pmid:26180542
              • 55. Baloch Z, Yue L, Feng Y, Tai W, Liu Y, Wang B, et al. Status of human papillomavirus infection in the ethnic population in Yunnan Province, China. Biomedical Research International. 2015; 314815. pmid:26819950
              • 56. Vidal AC, Skaar D, Maguire R, Dodor S, Musselwhite LW, Bartlett JA, et al. IL-10, IL15, IL-17 and GMCSF levels in cervical cancer tissue of Tanzanian women infected with HPV/16/18 vs. non-HPV16/18 genotypes. Infectious Agents and Cancer. 2015;10(10). pmid:25810759
              • 57. Howitt BE, Herfs M, Tomoka T, Kamiza S, Gheit T, Tommasino M, et al. Comprehensive Human Papillomavirus Genotyping in Cervical Squamous Cell Carcinomas and Its Relevance to Cervical Cancer Prevention in Malawian Women. J Glob Oncol. 2017;3(3): 227–234. pmid:28717764
              • 58. Chambuso RS, Rebello G, Kaambo E. Personalised human papillomavirus vaccination for persistence of immunity for cervical cancer prevention: A critical review with experts’ opinions. Front Oncol. 2020; 10(548). pmid:32391264
              • 59. Vacarella S, Franceschi S, Herrero R, Schiffman M, Rodriguez AC, Hildesheim A, et al. Clustering of multiple human papillomavirus infections in women from a population-based study in Guanacaste, Costa Rica. Journal of Infectious Diseases. 2011; 204(3): 385–390.
              • 60. Romero-Pastrana F. Detection and typing of human papilloma virus by multiplex PCR with type specific primers. International Scholarly Research Notices. 2012;186915. pmid:23724318
              • 61. Samwel K, Kahesa C, Mwaiselage J, Gonzalez D, West JT, Wood C. Analytical performance of a low-cost multiplex polymerase genotyping assay for use in Sub- Saharan Africa. J Med Virol. 2019;91(2): 308–316. pmid:30281790
              • 62. Calleja Macias IE, Kalantari M, Huh J, Ortiz-Lopez R, Rojas-Martinez A, Gonzalez-Guerrero JF, et al. Genomic diversity of human papillomavirus-16, 18, 31, and 35 isolates in a Mexican population and relationship to European, African and Native American variants. Virology. 2004; 319(2): 315–323. pmid:14980491
              • 63. Fitzpatrick MB, Hahn Z, Dube-Mandishora RS, Dao J, Weber J, Huang C, et al. Whole genome analysis of cervical human papillomavirus type 35 from rural Zimbabwean women. Sci Rep. 2020;10: 7001. pmid:32332798
              • 64. Massad SL, Xie X, Burk RD, D’Souza G, Darragh TM, Minkoff H, et al. Association of cervical precancer with human papillomavirus types other than 16 among HIV co-infected women. Am J Obstet Gyneol. 2015;214(3): 354.e1–6. pmid:26433170
              • 65. Castle PE, Burk RD, Massad LS, Eltou IE, Hall CB, Hessol NA, et al. Epidemiological evidence that common HPV types may be commonn because of their ability to evade immune surveillance: Results from the Women’s Integracy HIV study. Cancer Epidemiology. 2019;146(12): 3320–3328.
              • 66. Arbyn M, Castellsague X, de Sanjose , Bruni L, Saraiya M, Bray F, et al. Worldwide burden of cervical cancer in 2008. Ann Oncol. 2011;22(12): 2675–2686. pmid:21471563
              • 67. Guan P, Howell-Jones , Li , Bruni L, de Sanjose S, Franceschi S, et al. Human papillomavirus types in 115, 789 HPV positive women: A Meta-analysis from cervical infection to cancer. Int J Cancer. 2012;131: 2349–2359. pmid:22323075
              • 68. De Vuyst H, Alemany L, Lacey C, Chibwesha CJ, Sahsrabuddhe V, Banura C, et al. The burden of human papillomavirus infections and related diseases in Sub Saharan Africa. Vaccine. 2013;31(5): F32–F46. pmid:24331746
              • 69. Vidal AC, Murphy SK, Hernandez BY, Vasquez B, Bartlett JA, Oneko O, et al. Distribution of HPV genotypes in cervical intraepithelial lesions and cervical cancer in Tanzanian women. Infect Agent Cancer. 2011;6(1):20. pmid:22081870
              • 70. Palefsky J. Human papillomavirus-related disease in people with HIV. Curr Opin HIV AIDS. 2009;4(1): 52–6. pmid:19339939
              • 71. Borok M, Hakim J, Kutner J, Mawhinney S, Simons EAF, Campbell T. Strategies to improve Kaposi Sarcoma Outcomes: An educational intervention in Zimbabwe. Disease Specific Cancer Control. 2014: 91–97.
              • 72. Chambuso RS, Shadrack S, Lidenge SL, Mwakibete N, Medeiros RM. Influence of HIV/AIDS on cervical cancer: A retrospective study from Tanzania. Journal of Global Oncology. 2016; 72(3). pmid:28717744
              • 73. Hawes SE, Critchlow CW, Faye Niang MA, Diouf MB, Diop A, Touré P, et al. Increased risk of high-grade cervical squamous intraepithelial lesions and invasive cervical cancer among African women with human immunodeficiency virus type 1 and 2 infections. J Infect Dis. 2003;188: 555–63. pmid:12898443
              • 74. Clifford GM, Polesel J, Rickenbach M, Dal Maso L, Keiser O, Kofler A, et al. Cancer risk in the Swiss HIV Cohort Study: Associations with immunodeficiency, smoking, and highly active antiretroviral therapy. J Natl Cancer Inst. 2005;97(6): 425–432. pmid:15770006
              • 75. Biggar RJ, Chaturvedi AK, Goedert JJ, Engels EA. AIDS-related cancer and severity of immunosuppression in persons with AIDS. J Natl Cancer Inst. 2007;99(12): 962–972. pmid:17565153
              • 76. Dal Maso L, Polesel J, Serraino D, Lise M, Piselli P, Falcini F, et al. Pattern of cancer risk in persons with AIDS in Italy in the HAART era. Br J Cancer. 2009;100(5): 840–847. pmid:19223894
              • 77. Anastos K, Hoover DR, Burk RD, Cajigas A, Shi Q, Singh DK, et al. Risk factors for cervical precancer and cancer in HIV-infected, HPV-positive Rwandan women. PLoS One. 2010;5(10): e13525. pmid:20976000
              • 78. Anderson J, Lu E, Sanghvi H, Kibwana S, Lu A. Cervical cancer screening and prevention for HIV-infected women in the developing world. Mol Biosyst. 2010;6: 1162–1172.
              • 79. Mwanahamuntu MH, Sahasrabuddhe VV, Kapambwe S, Pfaendler KS, Chibwesha C, Mkumba G, et al. Advancing cervical cancer prevention initiatives in resource-constrained settings: insights from the Cervical Cancer Prevention Program in Zambia. PLoS Med. 2011;8(5): e1001032. pmid:21610859
              • 80. Mbulaiteye SM, Bhatia K, Adebamowo C, Sasco AJ. HIV and cancer in Africa: mutual collaboration between HIV and cancer programs may provide timely research and public health data. Infectious Agents and Cancer. 2011;6(1): 16–28. pmid:22004990
              • 81. Onogbu U, Almujtaba M, Modibbo F, Lawal I, Offiong R, Olaniyan O, et al. Cervical cancer risk factors among HIV-infected Nigerian women. BMC Public Health. 2013;13(582). pmid:23767681
              • 82. Chambuso RS, Ramesar R, Kaambo E, Denny L, Passmore J, Williamson AL, et al. Human Leucocyte Antigent (HLA) Class II-DRB and DQB alleles and the association with cervical cancer in HIV/HPV co-infected women in South Africa. Journal of Cancer. 2019;10(10):2145–2152. pmid:31258717
              • 83. Ramogola-Masire D, McGrath CM, Barnhart KT, Friedman HM, Zetola NM. Subtype distribution of human papillomavirus in HIV infected women with intraepithelial neoplasia stages 2 and 3 in Botswana. Int J Gynecol Pathol. 2011;30(6): 591–6. pmid:21979597
              • 84. Zohoncon TM, Bisseye C, Djigma FW, Yonli AT, Campaore TR, Sagna T, et al. Prevalence of HPV high-risk genotypes in three cohorts of women in Ouagadougou (Burkina Faso). Mediterr J Hematol Infect Dis. 2013; 5(1): e2013050.
              • 85. Gaester K, Fonseca LAM, Luiz O, Assone T, Fontes AS, Costa F, et al. Human papillomavirus infection in oral fluids of HIV-1-positive men: prevalence and risk factors. Nature Scientific Reports. 2014;4(6592). pmid:25322857
              • 86. Adebamowo SN, Famooto A, Dareng EO, Olawande O, Olaniyan O, Offiong R, et al. Clearance of type-specific, low risk and high risk cervical human papillomavirus infections in HIV negative and HIV positive women. J Glob Oncol. 2018;4(4): 1–12. pmid:30125130
              • 87. Kelly H, Weiss HA, Benavente Y, de Sanjose S, Mayaud P. Association of antiretroviral therapy with high-risk human papillomavirus, cervical intraepithelial neoplasia, and invasive cervical cancer in women living with HIV: a systematic review and meta-analysis. The Lancet HIV. 2018;5(1): e45–e58. pmid:29107561
              • 88. Mendez-Martinez R, Maldonaldo-Frias S, Vazquez-Vega S, Caro-Vega Y, Rendon-Maldonado JG, Guido-Jimenez M, et al. High prevalent human papillomavirus infections of the oral cavity of asymptomatic HIV-positive men. BMC Infectious Diseases. 2020; 20(27). pmid:31924186
              • 89. Lebelo RL, Bogers JJ, Thys S, Depuydt C, Benoy I, Selabe SG, et al. Detection, genotyping and quantitation of multiple HPV infections in South African women with squamous cell carcinoma. J Med Virol. 2015;87(9): 1594–1600. pmid:26037775
              • 90. Bateman AC, Katundu K, Polepole P, Shibemba A, Mwanahamuntu M, Dittmer DP, et al. Identification of human papillomaviruses from formalin-fixed, paraffin- embedded pre-cancer and invasive cervical cancer specimens in Zambia: A cross-sectional study. Virol J. 2015;12:2. pmid:25591541
              • 91. Kaliff M, Sorbe B, Mordhorst LB, Helenius G, Karlsson MG, Lillsunde-Larsson G. Findings of multiple HPV genotypes in cervical carcinoma are associated with poor cancer-specific survival in a Swedish cohort of cervical cancer primarily treated with radiotherapy. Oncotarget. 2018;9(27): 18786–18796. pmid:29721161
              • 92. Rousseau MC, Villa LL, Costa MC, Abrahamowicz M, Rohan TE, Franco E, et al. Occurrence of cervical infection with multiple Human Papillomavirus Types is associated with age and cytologic abnormalities. Sexually Transmitted Diseases. 2003;30(7): 581–587. pmid:12838088
              • 93. Carozzi F, Ronco G, Gillio-Tos A, De Marco L, Del Mistro A, Girlando S, et al. Concurrent infections with multiple human papillomavirus (HPV) types in the New Technologies for Cervical Cancer (NTCC) screening study. European Journal of Cancer. 2012;48(11):1633–1637. pmid:22088483
              • 94. Dickson EL, Vogel RI, Bliss RL, Downs LS. Multiple-type HPV infections: a cross-sectional analysis of the prevalence of specific types in 309,000 women referred for HPV testing at the time of cervical cytology. Int J Gynecol Cancer. 2013;23(7): pmid:23970156
              • 95. Liaw KL, Hildesheim A, Burk RD, Gravitt P, Wacholder S, Manos MM, et al. A prospective study of human papillomavirus (HPV) type 16 DNA detection by polymerase chain reaction and its association with acquisition and persistence of other HPV types. J Infect Dis. 2001;183(1): 8–15. pmid:11087198
              • 96. Plummer M, Schiffman M, Castle PE, Maucort-Boulch D, Wheeler CM, ALTS Group. A 2-year prospective study of human papillomavirus persistence among women with a cytological diagnosis of atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion. J Infect Dis. 2007;195(11): 1582–9. pmid:17471427
              • 97. Schiller JT, Castellsagué X, Villa LL, Hildesheim A (2008) An update of prophylactic human papillomavirus L1 virus-like particle vaccine clinical trial results. Vaccine. 2008; 26(10):K53–61. pmid:18847557
              • 98. Chaturvedi AK, Katki HA, Hildesheim A, Rodríguez AC, Quint W, Schiffman M, et al. Human papillomavirus infection with multiple types: pattern of coinfection and risk of cervical disease. J Infect Dis. 2011;203(7): 910–20. pmid:21402543
              • 99. Syse A, Lyngstad TH. In sickness and in health: the role of marital partners in cancer survival. SSM Popul Health. 2016;3: 99–110. pmid:29349208
              • 100. Altobelli E, Rapacchietta L, Profeta VF, Fagnano R. HPV-vaccination and cancer cervical screening in 53 WHO European Countries: An update on prevention programs according to income level. Cancer Med. 2019;8: 2524–2534. pmid:30993902
              • 101. Paavonen J, Naud P, Slameron J, Wheeler CM, Chow SN, Apter D, et al. Efficacy of human papillomvirus (HPV)-16/18 AS04-adjuvanted vaccine against cervical infection and precancer caused by oncogenic HPV types (PATRICIA): Final analysis of a double blind, randomised study in young women. Lancet. 2009;374(9686): 301–314. pmid:19586656
              • 102. Brown DR, Kjaer SK, Sigurdsson K, Iversen OE, Hernandez-Avila M, Wheeler CM, et al. The impact of quadrivalent human papillomavirus (HPV; types 6, 11, 16 and 18) L1 virus-like particle vaccine on infection and disease due to oncogenic non vaccine HPV types in generally HPV-naive women 16–26 years. J Infect Dise. 2009;199: 926–935.
              • 103. Weinberg A, Song LY, Saah A, Brown M, Moscicki AB, Meyer WA, et al. Humoral, mucosal and cell-mediated immunity against vaccine and non-vaccine genotypes after administration of quadrivalent human human papillomavirus vaccine to HIV-infected children. J Infect Dis. 2012; 206(8): 1309–1318. pmid:22859825
              • 104. Van Kriekinge G, Castellsague X, Cibula D, Demarteau N. Estimation of the potential overall impact of human papillomavirus vaccination on cervical cancer cases and deaths, Vaccine. 2014;32(6): 733–739. pmid:24291200
              • 105. Toft L, Tolstrup M, Storgaard M, Ostergaard L, Sorgaard OS. Vaccination against oncogenic human papillomavirus infection in HIV-infected populations: Review of current status and future perspectives. Sex Health. 2014a;11(6): 511–523.
              • 106. Toft L, Tolstrup M, Muller M, Sehr P, Bonde J, Storgaard M, et al. Comparison of the immunogenecity of reactogenicity of cervarix and gardasil human papillomavirus vaccines for oncogenic non-vccine serotypes HPV31, HPV33, and HPV45 in HIV-infected adults. Hum Vaccin Immunother. 2014b;10(5): 1147–1154.
              • 107. Adebamowo SN, Dareng EO, Famooto AO, Offiong R, Olaniyan O, Obende K, et al. Cohort Profile: African Collaborative Center for Microbiome and Genomics Research’s (ACCME’s) Human papillomavirus (HPV) and Cervical cancer study. Int J Epidemiol. 2017b;46(6): 1745–1745j.
              • 108. Cho C, Lo Y, Hung M, Lai C, Chen C, Wu K. Risk of cancer in patients with genital warts: A nationwide, population-based cohort study in Taiwan. PLoS One. 2017;12(8): e0183183. pmid:28806741
              • 109. Kjetland EF, Ndhlovu PD, Mduluza T, Deschooleester V, Midzi N, Gomo E, et al. The effects of genital schistosoma haematobium on human papillomavirus and the development of cervical neoplasia after five years in a Zimbabwean population. Eur J Gynaecol Oncol. 2010;31(2): 169–73. pmid:20527233