The high incidence of hepatitis B infection in Africa and parts of Asia is thought to be causally associated with increased incidence of which of the following malignancies?

a. Hepatocellular carcinoma

Although a genetic predisposition exists for some cancers, most available information favors environmental variation as the major contributor to the disparate geographic incidence of different cancer types. In many cases, the high incidence of a specific cancer in a particular region or country is linked to a specific causative agent. The chewing of a betel nut, tobacco, and lime mixture in regions of India has resulted in a high incidence of oropharyngeal tumors. The high incidence of gastric carcinoma in Japan is linked to a diet of smoked and highly salted foods, and food contaminated with aflatoxin. The high incidence of hepatitis B infections in parts of Africa and China is thought responsible for the high incidence of hepatocellular carcinoma in these regions. Geographic differences in several other common solid tumors are less clearly explained. Breast and colon carcinomas are common in North America, but rare in Africa and Asia. Carcinomas of the stomach, esophagus, and cervix are more common in developed countries.