Epidemiologic Study of Hepatocellular Carcinoma in the US

Inclusion Criteria for HCC cases: * a diagnosis of primary liver cancer (excluding secondary tumors) * a diagnosis of hepatocellular carcinoma if histology is available (excluding those diagnosed in intrahepatic bile duct, bile canals, biliary passages, canaliculi, gall duct and gallbladder) * a diagnosis of hepatocellular carcinoma with or without microscopic evaluation (including those diagnosed with clinical evidence, lab tests and direct visualization or radiographic and other imaging evidence) * a histology of primary hepatocellular carcinoma when the patients had a prior diagnosis of other forms of cancer (excluding those who had no histological diagnosis of hepatocellular carcinoma while having a prior history of other cancer; * age at diagnosis between 35 and 84 years * living in Connecticut, New Jersey, New York, or Hawaii for at least a year as regular residents. Exclusion Criteria for HCC cases: * uncertain diagnoses or classification of malignancy, such as unknown origin * a diagnosis of primary tumors in other organs, not in the liver * unable to communicate well enough in English or Spanish * having medical conditions, such as mental disorders, that prevent the subject from providing reasonably comprehensible information or from being able to give informed consent. * diagnosed at age \<35 years or \>84 years * temporary residents of New Jersey, Connecticut, New York, or Hawaii Inclusion Criteria for control subjects: * age between 35 and 84 years * living in New Jersey or Connecticut for at least a year as regular residents * able to communicate well in English or Spanish * having no medical conditions, such as mental disorders, that prevent them from providing adequately comprehensible information * potential subjects with a previous history of cancer are eligible. Exclusion Criteria for control subjects: * age \< 35 years or \> 84 years * temporary residents of New Jersey or Connecticut * unable to speak English or Spanish * cannot provide adequately comprehensible information