Serum microcystin levels positively linked with risk of hepatocellular carcinoma: A case‐control study in southwest China

Microcystins have been reported to be carcinogenic by animal and cell experimentation, but there are no data on the linkage between serum microcystins and hepatocellular carcinoma (HCC) risk in humans. We conducted a clinical casecontrol study to investigate the association between serum microcystins and HCC risk after controlling several known risk factors, such as hepatitis B virus, alcohol, and aflatoxin. From December 2013 to May 2016, 214 patients newly diagnosed with HCC along with 214 controls (frequency-matched by age and sex) were recruited from three hospitals in Chongqing, southwest China. Basic information on lifestyle and history of disease was obtained by questionnaire. Blood samples were collected and analyzed for serum microcystin-LR (MC-LR) and aflatoxin-albumin adduct by enzyme-linked immunosorbent assay and for hepatitis B surface antigen status by chemiluminescence assay. Binary logistic regression analyses were performed to assess the independent effects of MC-LR and its joint effects with other factors on HCC risk. The adjusted odds ratio for HCC risk by serum MC-LR was 2.9 (95% confidence interval [CI], 1.5-5.5) in all patients. Notably, a clear relationship between increased MC-LR level (Q2, Q3, and Q4) and HCC risk was observed with elevated adjusted odds ratios (1.3, 2.6, and 4.0, respectively). Positive interactions with the additive model were investigated between MC-LR and hepatitis B virus infection (synergism index53.0; 95% CI, 2.0-4.5) and between MC-LR and alcohol (synergism index54.0; 95% CI, 1.7-9.5), while a negative interaction was found between MC-LR and aflatoxin (synergism index50.4; 95% CI, 0.3-0.7). Additionally, serum MC-LR was significantly associated with tumor differentiation (r=-0.228, P < 0.001). Conclusion: We provide evidence that serum MC-LR was an independent risk factor for HCC in humans, with an obvious positive interaction with hepatitis B virus and alcohol but a negative interaction with aflatoxin.