Assessment of safety/risk vs. Public health concerns: Aflatoxins and hepatocarcinoma

摘要

Hepatocellular carcinoma, (HCC) is a serious health problem. It is prevalent in certain parts of the world where food contamination with aflatoxin is common. Aflatoxin, especially AFB1, has been shown to induce HCC in many species of laboratory and wild animals, including subhuman primates. Carcinogenesis studies have demonstrated that AFB1 is a potent genotoxic carcinogen. After bioactivation it may covalently bind with protein and with DNA. The former reaction is positively correlated with AFB1 exposure, and the latter signifies initiation of the carcinogenesis process.With these biomarkers, epidemiological studies have amply demonstrated the etiological role of aflatoxin in HCC. However, hepatitis B virus also contributes to the development of HCC. Risks and VSD (virtual safe dose) have been estimated from animal and epidemiological studies. These estimates further confirm that AFB1 is a potent carcinogen. Furthermore, the effects of AFB1 exposure and hepatitis B are synergistic. Some preventive measures, such as lowering the contamination level of AFB1 in food and appropriate vaccination programs, have been implemented in many parts of the world. Chemopreventive agents. which may abolish or reduce the effects of AFB1 are being tested for their effectiveness.