Clinical Significance Of Detecting HTERTmRNA In Human Hepatocellular Carcinoma Tissue

PrefaceHuman hepatocellular carcinoma (HCC) is among the most prevalent and lethal cancers in humans. Telomerase is expressed in most human cancers and immortal cell lines but is inactive in normal somatic cell lines or tissue. Recent reports support the concept that activation of telomerase may be an important and obligate step in the development of most malignant tumors, including HCC. The human telomerase catalytic subunit (hTERT) has been shown to be a rate - limiting determinant of the enzymatic activity of human telomerase. We measured hTERTmRNA levels in HCC using in situ hybridization to determine its use as a possible biomarker for prognosis and early diagnosis of HCC.Materials1. Sample collection70 patients were enrolled in this study. 9 fresh HCC samples after operation were obtained from Liaoning tumor hospital during 2004 - 2005. 61 paraffin -embedded samples during 2002 - 2003, including 28 HCC and 33 liver cirrhosis , were collected from our hospital.2. ReagentsTERT situ hybridization kit, DAB, PBS, DEPC, POLY - L - LYSINE , 2 × SSC, 0. 5 × SSC, 0. 2 × SSC, 30% H₂O₂,4% Polyformalin, 20% Glycerine, methanolMethods1. Situ hybridizationAccording to the introduce of TERT situ hybridization kit.2. ControlsBlank control—PBS instead of hybridization solutionNegative control—The slides were digested with Rnase at 37°C for 1 hourPositive control—Positive samples of colon cancer3. Judging criterionPositive signals of hTERTmRNA distribute in the cytoplasma as brown -yellow granulae. The signal intensity of hTERTmRNA expression is semiquanti-tated as strong positive, weak positive or negative.4. AnalysisData were statistically analyzed by the x - test and t - test with SPSS software.Results1. The positive rate of hTERTmRNA expression in HCC was much higher than that in liver cirrhosis or pericancerous tissue.2. Close relationship could be observed between the expression of hTERT gene and cell diffrentiation in HCC. Tumor size, HBV infection and AFP concentration in serum did not affect hTERTmRNA expression.3. There is significant correlation between hTERT gene and the survival rate of HCC patients after operation. The group of patients that hTERTmRNA expression in HCC was weak positive lived much longer than the strong positive group.DiscussionHepatocellular carcinoma ( HCC) is one of the most common malignanttumor occurring in males in the world with the poor prognosis. In the past few years, the telomerase has emerged as a promissory marker for the diagnosis and prognostic criteria in HCC and other tumors. Human telomerase reverse tran-scriptase (hTERT) is a human telomerase catalytic subunit. Telomerase reactivation in cancer correlates with the upregulation of TERT. A variety of studies demonstrated telomerase reactivation in different human cancers, including > 80% of HCC, indicating that telomerase reactivation is a rate - limiting step in carcinogenesis. In this study, hTERT has been found active in most HCC and negative or weak in pericancerous hepatic tissue or liver cirrhosis. It also sug-gusts that hTERTmRNA expression occurs at the cancer stage. On the molecular level, the activation of c - myc and integration of hepatitis B virus in the TERT promoter region have been linked to the reactivation of telomerase in HCC. We also found the expression of hTERTmRNA was related to tumor differentiation. The positive signal intensity is more pronounced in poorly differentiated tumors. It shows hTERTmRNA plays an important role in the process of tumor cell differentiation. Furthermore, hTERTmRNA expression had been shown to correlate well with the survival period of HCC patients after operation, pointing to its use as a possible marker for the prognosis in HCC.ConclusionTelomerase activity is nessessary for HCC cell proliferation and malignant transformation. hTERTmRNA may be a biomarker for prognosis and early diagnosis of HCC.