**DNA Repair Capacity-Related to Genetic Polymorphisms of DNA Repair Genes and Aflatoxin B1-Related Hepatocellular Carcinoma Among Chinese Population**

Xi-Dai Long1,2 et al.\*

*1Department of Pathology, Youjiang Medical College for Nationalities 2Department of Pathology, Shanghai Jiao Tong University School of Medicine China* 

### **1. Introduction**

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 5 year 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

<sup>\*</sup> Jin-Guang Yao3, Zhi Zeng2, Cen-Han Huang3, Pinhu Liao3, Zan-Song Huang3, Yong-Zhi Huang1, Fu-Zhi Ban4, Xiao-Yin Huang1, Li-Min Yao5, Lu-Dan Fan6, and Guo-Hui Fu2

*<sup>3</sup>Department of Medicine, Youjiang Medical College for Nationalities, China.* 

*<sup>4</sup>Department of Medicine, the Southwestern Affiliated Hospital of Youjiang Medical College for Nationalities, China.* 

*<sup>5</sup>Department of Imaging Medicine (Grade 2008), Youjiang Medical College for Nationalities, China.* 

*<sup>6</sup>Department of Clinic Medicine (Grade 2009), Youjiang Medical College for Nationalities, China.* 

DNA Repair Capacity-Related to Genetic Polymorphisms of DNA Repair

Genes and Aflatoxin B1-Related Hepatocellular Carcinoma Among Chinese Population 507

Fig. 1. The mortality rates of HCC in China during 1973 and 2005. Total mortality rates (A), regardless of in urban areas or countryside areas (B), were significantly increasing from during 1973 and 1975 to during 1990 and 1992 or to during 2004 and 2005. This increasing

mortality rates were more remarkable among male population (C).

carcinogenesis may be of importance in determining individual susceptibility to HCC (3, 9, 12). Therefore, the existence of low penetrate genetic polymorphisms may explain the reason why only a small portion of individuals, even in high-risk areas, develop HCC in their life span. This study reviews recent efforts in identifying genetic variants which may have impact on risk of HCC.
