Furthermore, the staining of cytokeratin 19 (CK19), a marker of biliary lineage cells, showed no immunoreactivity to CK19 in the tumor tissues from the C57-HBV mice delivered with sgp53/Pten even though significant CK19 staining could be detected in the adjacent non-tumor tissues (Fig. 4, third row). The gene discussed is KRT19; the disease is neoplasm.