Necropsy and clinical data show that primary hepatocellular carcinoma (PHC) is the commonest cancer among the Senoi (a Malaysian aboringine group). The other aboringine tribes do not appear to have this high predilection for liver cancer. In the necropsy series, PHS was present in 10 out of 22 Senoi patients with cirrhosis. All the 22 livers contained hepatocytes that stained with Shikata's orcein stain and specific immunoperoxidase and immunofluorescent stains for hepatitis B antigen (HBAg). This observation raises the strong possibility that hepatitis B may be an important etiologic factor in the development of cirrhosis and PHC in the Senoi. The reason for the high susceptibility of the Senoi for HB virus infection is not clear, and the role of aflatoxin in the pathogenesis of PHC in the Senoi has yet to be determined. That the Senoi are a numerically small community, maintaining their own unique dietary and social customs and living in readily accessible areas in the Malaysian jungle, makes them an ideal population for the study of factors in the etiology of liver cancer.
Chronic hepatitis B virus (HBV) infection constitutes a major public health problem particularly in developing countries in East Asia, South-East Asia, the Pacific Basin and Africa. In Malaysia, a developing nation in the South East Asian region, the chronic HBV carrier rate varies between < 1% to about 10% depending on the ethnic group studied. The highest frequency is seen among the Chinese, followed by the Malays and lastly the Indians, with a male preponderance of between 2 : 1 and 3 : 1. Exposure to the virus among the adult population is estimated to be about 15%, 26% and 36% among the Indians, Malays and Chinese respectively. Serological study of adult chronic HBV carriers showed a frequency of HBe antigenemia of about 35%, with a significant decreasing trend with age. HBV DNA status generally correlated with the HBe status. An atypical profile of anti-HBe associated with serum HBV DNA is found in some carriers; in most instances, this is related to seroconversion from HBe antigenemia to anti-HBe. Chronic complications of HBV infection include the development of hepatocellular carcinoma (HCC), the occurrence of which closely parallel that of HBsAg carrier rate. In Malaysia, HCC is the third most common malignant neoplasm and among the 10 leading causes of death. About 80% of our HCC cases are HBV associated. All 3 ethnic groups are afflicted, the highest frequency being among the Chinese. Males show a disproportionate risk with an odds ratio of 3.93 (p < 0.0001).