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Primary liver cancer (PLC) is the sixth most commonly occurring cancer and the third most common cause of cancer deaths in the world (1). This tumor has two main pathological types: hepatocellular carcinoma (HCC) and cholangiocellular carcinoma. HCC, the most common pathological form of PLC, occurs more often in specific regions which include eastern and southeastern Asia, Melanesia, and sub-Saharan Africa (1, 2). Once diagnosed, survival rates for HCC are poor: 75% of patients die within 1 year, and 5year survival rate is only 3 5% (3, 4). Therefore, insight into the tumorigenesis mechanisms of HCC will broaden and deepen implications in understanding and preventing occurrence of the cancer. It has been known that chronic infection with hepatitis virus [including hepatitis virus B (HBV) and hepatitis virus C (HCV)] is the most common cause of HCC worldwide (3). In sub-Saharan Africa and Southern China, chronic exposure of aflatoxin B1 (AFB1) may present a special environmental hazard, especially in individuals chronically infected with HBV (1, 2, 5-8). However, increasing epidemiological evidence has exhibited that although many people are exposed to these risk factors, only a relatively small proportion of chronic infectors or exposure person develop HCC (3, 9, 10). This indicates an individual susceptibility related to genetic factors such as DNA repair capacity might be associated with HCC carcinogenesis (3, 11). In recent years, evidence has been accumulated to support the hypothesis that common genetic polymorphisms in genes involved in long process of |
