Stem cell expression profile in hepatocellular carcinoma, small cell dysplasia, and cirrhosis.

Abstract

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide with various etiologies and its incidence still continues to increase. Tumors with progenitor/stem cell (P/SC) immunophenotype are currently the main focus of interest. Human hepatic P/SCs are located in ductal plates in fetal and neonatal livers and they remain relatively constant throughout life. Enhanced self-renewal level of normal hepatic P/SCs serves as an early event in hepatocarcinogenesis. Approximately 40% of HCCs arise from P/SCs and these cells have a critical role in development and progression of HCC. Thus, CD133 expression was found to be upregulated during early liver restoration. In spite of the increasing evidence of the impact of cancer stem cells (CSCs) in hepatocarcinogenesis, the role of CSCs in the sequence of cirrhosis (Crh)-dysplastic nodules (DN)-HCC is still not clear. In our recent research, we investigated the expression rate and staining patterns of CD133 and CD90 in Crh, small cell dysplasia, and HCC. We also evaluated the relationship between the expression rates of CSC markers and the etiology of liver diseases. Among the P/SC markers, we like to attract more attention to CD133 and CD90. Both CD133 and CD90 expressions were higher in poorly differentiated HCC cases than well differentiated ones. According to the etiology, we found that the highest staining rate for CD133 in HCC cases developed in a cirrhotic background with chronic hepatitis B and D co-infection. The highest rate for CD90 was determined in HCC cases with chronic hepatitis C. Since Crh is the end-stage of chronic injury with continuing regeneration, detection of accompanying P/SC activation by CSC markers in suspicious nodules may suggest the initiation of early phases of hepatocarcinogenesis. Some other immunophenotypical features such as Glypican 3, heat shock protein-70, and glutamine synthetase stainings are also being used to diagnose precursor lesions. Facing the emerging concept of personalized treatment strategy, it is obvious that the studies in hepatocarcinogenesis related to the theory of CSCs will provide new ideas on genesis, development, and metastasis of HCC and will bring new insights for the diagnosis and treatment of these tumors.