Fig 1.
CRC tissues show constitutively over-phosphorylated Stat3 (p-Stat3) and overexpressed IL-17 than adjacent normal tissues (ANT) using IHC method with specific antibodies.
Six representative IHC staining panels are shown. Antibody-staining against p-Stat3 is mainly localized in the nucleus (A, B and C, positive staining of yellow-brown), while antibody-staining against IL-17 is primarily in the cytoplasm (D, E and F, positive staining of yellow-brown). A and B came from paired tissues of the same patient but C was from an unrelated tissue. D and E came from paired tissues of the same patient but F was from an unrelated tissue. It can be seen that p-Stat3 is strongly stained in CRC (2) (C, scored as 3+) as compared with another CRC (1) (B, scored as 2+) or ANT tissue (A, scored as negative or 0). Similarly for IL-17, CRC (2) tissue shows strong staining (F, scored as 3+) compared with another CRC (1) (E, scored as 1+) but ANT shows little or no staining (D, scored as negative or 0). Microscopic magnification is X200 with inserts of X400. ANT = adjacent normal tissues and CRC = colorectal cancer, respectively.
Table 1.
Scoring criteria of Immunohistochemistry (IHC) assay with specific antibodies used in this study.
Table 2.
Colorectal cancer (CRC) tissues have a higher rate of high-risk HPV infection, than both adjacent normal tissues (ANT) and colorectal adenoma tissues (CRA).
Table 3.
HPV Infection Only Correlates with Late Clinical Stages among Many Clinicopathological Characteristics of CRC.
Table 4.
More CRC Tissues Show Strong Positive Stainings (2+/3+) of Constitutive p-Stat3 and Expressed IL-17 than ANT Tissues.
Fig 2.
CRC tissues show over-phosphorylation of Stat3 (p-Stat3) and overexpression of IL-17 when compared with ANT.
(A) Based on the scoring criteria (Table 1), pooled scores for p-Stat3 or IL-17 are compared between CRC and ANT individuals using t-test and the data are expressed as mean ± standard deviation (M±SD). As seen, constitutive p-Stat3 is higher in CRC than in ANT (M±SD, 4.5±3.0 vs 3.1±2.5, P = 0.001). Similarly, expressed IL-17 is also higher in CRC than in ANT (M±SD, 5.0±2.7 vs 3.3±2.4, P<0.001). (B) Comparison between CRC and ANT for the number of individuals (%) with varying staining intensities using χ2 test. As shown for p-Stat3, CRC category has less individuals scored as 0 than ANT category (4.2% vs 23.3%, P<0.001). To the contrary, CRC has many more individuals scored as strong positives (2+/3+) than ANT (50.5% vs 18.9%, P<0.001). A striking similarity is true for IL-17, of which CRC category has less individuals scored as 0 than ANT category (2.1% vs 16.7%, P<0.001) but again, CRC has many more individuals scored as stronger positives 2+/3+ than ANT (45.3% vs 22.2%, P<0.001). For both p-Stat3 and IL-17, staining intensity of weak positivity (1+) is not significantly different between CRC and ANT categories (P = 0.07 and P = 0.25, respectively). ANT indicates adjacent normal tissues and CRC depicts colorectal cancer, respectively.
Table 5.
p-Stat3 and IL-17 Expression Are Not Correlated with CRC Patients’ Clinicopathological Characteristics.
Table 6.
Cross correlation analyses reveal strong relationships among HPV infection, activated p-Stat3 and expressed IL-17 in CRC tissues but not in non-cancerous ANT tissues.