TO THE EDITORrnHepatocellular carcinoma (HCC) is thought to develop through a multistep process[1]. A long history of viral hepatitis or prolonged exposure to environmental toxins predisposes liver cells to mutations of the genes critical in the control of hepatocyte growth. In fact, both activation of cellular oncogenes and inactivation of tumorsuppressor genes are involved in the development of HCC. Activation of oncogenes by hepatitis virus integration has been shown in the woodchuck animal model[2],although the significance of this finding in human hepatocarcinogenesis is still under investigation.