Hepatic progenitor cells in liver cancers from Asian children

Background/Aims: Hepatoblastoma (HB) and hepatocellular carcinoma (HCC) are the two most common primary malignant liver tumours in children. Hepatic progenitor cells have been described and can be stained with K19, EpCAM and CD117. We investigated the morphology and staining patterns of primary liver tumours in Asian children. Methods: Four pathologists studied slides from 39 paediatric patients from Vietnam and Korea aged 8 months to 16 years. We performed immunohistochemical stains for K19, EpCAM and CD117, and polymerase chain reaction for tissue hepatitis B virus (HBV) DNA and hepatitis C virus (HCV) RNA. Results: There was agreement on the diagnosis of 24 cases of HCC and 10 cases of HB (one recurrent case). The diagnosis was split for six cases (HCC/HB). All 20 cases of HCC tested were HBV DNA+ and HCV RNA-. All nine cases of HB tested were HBV DNA-, while one was HCV RNA+. Of four HCC/HB cases tested, three were HBV DNA+ and all were HCV RNA-. By immunohistochemistry, 8/24 (33%) cases of HCC were K19+ and 18/24 (75%) were EpCAM+, 5/10 (50%) cases of HB were K19+ and 7/10 (70%) were EpCAM+ and 3/6 (50%) cases of HCC/HB were K19+ and 5/6 (83%) were EpCAM+. CD117 was negative in all 38 cases tested. Paediatric HCC has a morphology different from adult HCC, sometimes resembling HB, and a larger proportion of paediatric tumours have progenitor cell features. Conclusions: HB and HCC in children may represent malignant transformation at an early stage in the cellular lineage and often arise from hepatic progenitor cells.