Primary HCC is a major cancer related to HBV viral infection in Asian countries, including Japan. Recently, the primary liver cancers are successfully treated by surgical resection including liver transplantation and non-surgical locoregional therapy.

Lamivudine has a high rate of antiviral resistance. Sequential anti-HBV treatment is commonly used for lamivudine resistance. We report 4 cases with rapid re-detection of HBV mutants during the lamivudine re-treatment.

This dreadful HBV is small in size. The genome of this virus is a partial double stranded circle. When made fully double stranded, this genome carries about 3000 base pairs, compared to 200 kilo base pairs of the genome of the smallpox virus.