Comparison of Subtypes of Hepatocellular Adenoma to Hepatocellular Carcinoma and Non-Neoplastic Liver Tissue in Terms of PTEN Expression.

PTEN is a tumour suppressor gene whose loss of function has been found to be present in a variety of neoplasms, both benign and malignant. In hepatocellular carcinoma (HCC), loss of PTEN is associated with poorly differentiated cancer, advanced clinical stage and tendency to recur. The extent and meaning of PTEN loss in hepatocellular adenoma (HA), one of the precursor lesions for HCC, has not yet been analysed. The aim of the present study was to evaluate the possible loss of PTEN expression in HA in the wider context of hepatocarcinogenesis. Immunohistochemical analysis of PTEN expression was performed in non-neoplastic liver tissue, HAs and HCCs. It has been found that the loss of PTEN was markedly present in poorly differentiated HCC, whereas well to moderately differentiated HCC showed similar levels of PTEN expression to non-neoplastic liver. HAs presented as a heterogeneous group, with loss of PTEN observed in the inflammatory and HNF1A-mutated subtype and relatively intact PTEN expression in HA with nuclear beta-catenin overexpression. This suggests that the loss of PTEN might occur both in HA and HCC, constituting different outcomes of the same molecular lesion in the various contexts of malignant or benign neoplasms.