Table 1.
Patient characteristics.
Fig 1.
Plasma brain natriuretic peptide (BNP) and serum C-reactive protein (CRP) levels in patients with and without cancer.
Both the BNP and CRP levels were significantly higher in the patients with cancer than in those without.
Fig 2.
BNP levels in patients with different stages of cancer.
Plasma BNP levels were significantly higher in cancer patients with stage IV than in patients with stage I, II, and III. There were no significant difference in BNP levels between cancer patients with stage I, II, and III. An ANOVA was used to assess the statistical significance followed by a Bonferroni correction.
Fig 3.
Relationship between BNP and CRP in patients with and without cancer.
In non-cancer patients, there was no significant correlation between BNP and CRP levels, but there was a significant positive correlation between BNP and CRP levels in cancer patients.
Fig 4.
A. Relationship between the BNP and creatinine levels in the patients with and without cancer. In the non-cancer patients, there was a significant correlation between the BNP and creatinine levels, but there was no correlation between the BNP and creatinine levels in the cancer patients. B. Relationship between the BNP and age in the patients with and without cancer. In the non-cancer patients, there was a significant correlation between the BNP level and age, but that correlation was not observed in the cancer patients. C. Relationship between the BNP and body mass index in the patients with and without cancer. There was no significant correlation between the BNP levels and body mass index in either the patients with cancer or those without.
Fig 5.
Relationship between the BNP and CRP levels in the patients with hematological cancers versus solid tumors.
In the patients with hematological cancers, there was no relationship between the BNP and CRP levels. In contrast, there was a significant relationship between the BNP and CRP levels in the patients with solid tumors.
Table 2.
Multiple regression analysis of the BNP levels and potential associated factors in patients with cancer.
Table 3.
Multiple regression analysis of the BNP levels and potential associated factors in patients without cancer.
Fig 6.
In 28 cured patients with solid cancers who underwent a radical surgery, the plasma BNP levels significantly decreased after the surgery (left panel, closed circles) (*p<0.01 vs the value before surgery).
On the other hand, in 7 relapsed or insufficiently treated patients with solid cancers, the plasma BNP levels did not change after the surgery (left panel, open circles). In 13 patients with hematological cancers, the plasma BNP levels tended to decrease after the chemotherapy, but it did not reach a statistical significance.
Fig 7.
Hypothesized relationship between cancer and the BNP level.
In the tumor microenvironment, inflammatory cells, including macrophages, produce various cytokines in response to tumor cells and tissue necrosis. In cardiomyocytes, BNP synthesis has been shown to be upregulated at the transcriptional level by inflammatory cytokines. Based on these previous findings and our present study, we hypothesized that the production of BNP might be increased in cancer patients by cancer-related inflammation independent of the cardiac function, renal function, and age.