Although hepatocellular carcinoma is relatively rare in the United States and Europe, it is probably the most common malignant tumor occurring in males in the world. The annual incidence of the disease world wide is estimated to be 1,000,000 cases, with a male to female ratio of about 4:1. In China, Taiwan, Korea, and sub-Saharan Africa, hepatocellular carcinoma ranks as one of the top four malignant tumors in adults, and the annual incidence of the disease is as high as 150 cases per 1,000,000 population.