Aflatoxin, Hepatitis and Worldwide Liver Cancer Risks
Aflatoxins are among the most potent mutagenic and carcinogenic substances known. Differential potency of aflatoxin among species can be partially attributed to differences in metabolism; however, current information on competing aspects of metabolic activation and detoxification of aflatoxin in various species does not identify an adequate animal model for humans. Risk of liver cancer is influenced by a number of factors, most notably carriage of hepatitis B virus as determined by the presence in serum of the hepatitis B surface antigen (HBsAg+ or HBsAg-). About 50 to 100% of liver cancer cases are estimated to be associated with persistent infection of hepatitis B (or C) virus. The potency of aflatoxin in HBsAg+ individuals is substantially higher (about a factor of 30) than the potency in HBsAg-individuals. Thus, reduction of the intake of aflatoxins in populations with a high prevalence of HBsAg+ individuals will have greater impact on reducing liver cancer rates than reductions in populations with a low prevalence of HbsAg+ individuals. The present analysis suggests that vaccination against hepatitis B (or protection against hepatits C), which reduces prevalence of carriers, would reduce the potency of the aflatoxins in vaccinated populations and reduce liver cancer risk.
KeywordsLiver Cancer Pool Urine Sample Aflatoxin Exposure Liver Cancer Case Adequate Animal Model
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- Deurric, S., Poynard, T., Buffet, L., and Valleron, A.-J., 1998, Trends in primary liver cancer.The Lancet351:215.Google Scholar
- El-Serag, H.B. and Mason, A.C., 2000, Rsisk factors for the rising rates of hepatocellular carcinoma in the United States.Gastroenterol. 118(4): Suppl 2. 3792.Google Scholar
- IARC, 1994, Hepatitis viruses, Monographs on the evaluation of carcinogenic risks to humans. IARC Sci. Publ. 59. Lyon, France.Google Scholar
- JECFA, 1998, Aflatoxins. Safety evaluation of certain food additives and contaminants. (The forty-ninth meeting of the Joint FAO/WHO Expert Committee on Food Additives.). WHO Food Additives Series, no. 40. World Health Organization, Geneva 1998. pp 359–468.Google Scholar
- Kensler, T.W., He, X., Otieno, M., Egner, P.A., Jacobson, L.P., Chen, B., Wang, J.S., Zhu, Y.R., Zhang, B.C., 1998, Oltipraz chemoprevention trial in Qidong, People’s Republic of China: modulation of serum aflatoxin albumin adduct biomarkers.Cancer Epidemiol. Biomarkers Prey.7:127.Google Scholar
- Sun, Z., Lu, P., Gail, M.H., Pee, D., Zhang Q Ming, L., Wang, J., Wu, Y., Liu, G., Wu, Y., and Zhu, Y., 1999, Increased risk of hepatocellular carcinoma in male hepatitis B surface antigen carriers with chronic hepatitis who have detectable urinary aflatoxin metabolite MI.Hepatol.30:379.CrossRefGoogle Scholar
- Wang, J.S., Qian, G.S., Zarba, A., He, X., Zhu, Y.R., Zhang, B.C., Jacobson, L., Gange, S.J., Munoz, A., Kensler, T.W., 1996, Temporal patterns of aflatoxin-albumin adducts in hepatitis B surface antigen positive and antigen-negative residents of Daxin, Qidong County, People’s Republic of China.Cancer Epidemiol. Biomarkers Prey.5:253–261.Google Scholar