Significance of Cytoplasmic Expression of Telomerase Reverse Transcriptase in Patients with Hepatocellular Carcinoma Undergoing Liver Resection

Abstract Telomerase reverse transcriptase (TERT) is reportedly expressed in various types of cancer. However, the significance of TERT expression in hepatocellular carcinoma (HCC) has not been fully evaluated. Herein, we evaluated TERT expression in resected HCC tumor tissues using immunohistochemistry. TERT expression was assessed in both the cytoplasm and the nucleus of HCC cells. The relationships between TERT expression and clinical characteristics were investigated. Among the 135 HCCs, TERT expression was positive only in the cytoplasm in 86 tumors (63.7%), was positive only in the nucleus in 3 tumors (2.2%), was positive in both the cytoplasm and the nucleus in 5 tumors (3.7%) and was negative in 41 tumors (30.4%). Cytoplasmic TERT expression was significantly associated with HBs antigen, poor tumor differentiation, and DNA-dependent protein kinase catalytic unit (DNA-PKcs) expression. However, TERT expression in the cytoplasm or in the nucleus was not significantly correlated with the overall or the recurrence-free survival periods. In conclusion, TERT was mainly expressed in the cytoplasm of HCC tissues. Cytoplasmic TERT expression is closely associated with HBV-related HCC and DNA-PKcs expression. The overexpression of TERT and DNA-PKcs arise from cccDNA and may be related to liver carcinogenesis in the presence of HBV infection.