Expression Of CAS In Primary Hepatic Carcinoma Tissues And Its Relationship With HBV Infection

Objective The cellular apoptosis susceptibility protein (CAS) has important roles in process of tumor necrosis factor (TNF)-induced apoptosis and cell proliferation in physiological and pathological conditions. Up-regulated expression of CAS is found in primary hepatic carcinoma(PHC). CAS may play an important role in the development of human PHC. In this study, we studied the expression of CAS protein in tissue specimens of PHC tumor, paracarcinoma, non-tumor liver cirrhosis and viral hepatitis in order to identify if CAS may serve as a marker of hepatocellular carcinoma (HCC) diagnosis and to explore the roles of CAS expression in HBV infection associated PHC.Methods The expression of CAS protein in sixty cases of PHC and its paracarcinoma tissues, forty non-tumor liver cirrhosis and hepatitis tissues was detected by using immunochemical method. The relationship between the expression level of CAS protein and clinical pathological factors of PHC was analyzed. Meanwhile, HBsAg, HBcAg and HBV DNA in forty three tissues with HBV infection were examined by immunohistochemistry and in situ hybridization respectively.Results CAS protein expression was mainly located in the cytoplasm of the tumor cells in neoplasm tissues. In all tumor cases, the positive rate of CAS expression was not significant difference between HCC and cholangio-cellular carcinomas(CCC) , but the staining intensity score of CAS in HCC was obviously higher than that in CCC(p<0.01). Among the tissues specimens, the expression of CAS protein was significantly higher in HCC than in its paracarcinomous tissues (p<0.01), and higher in paracarcinomas tissues than in non-tumor liver cirrhosis and hepatitis tissues (p<0.01). Poorly differentiated tumors immunochemically stained stronger than moderately or well differentiated (p<0.01). CAS expression did not have a statistically significant correlation with either the age, tumor size or tumor invasion, intro-portal vein emboli in HCC cases (p>0.05). CAS is expressed at higher levels in HBV-infected PHC tissues than in non-HBV infection(p<0.01), which was positively correlated with HBV DNA examination in tissues (r = 0.367, p<0.05).Conclusion In our study, the various expression of CAS protein among HBV infection associated HCC tumor tissues, paracacinoma tissues cirrhosis and viral hepatitis tissues, which suggested that CAS might play an important role in the initiation of HCC through up-regulating expression of CAS. Since CAS immunostaining positive rate was much higher in HCC than that in CCC, and the intensity of CAS expression in HCC closely related with tumor differentiation, we deduced that CAS might serve as a marker for HCC diagnosis and differentiation estimation.