Expression of p53, Rb, bcl-2 Proteins and Ki-67 Labeling Index in Intrahepatic Cholangiocarcinoma

ABSTRACT

BACKGROUND: The development and progression of a tumor can be determined by a complex multistep process involving the activation of oncogenes and the inactivation of tumor suppressor genes. The purpose of this study is to investigate the expression of p53, Rb, bcl-2 protein and Ki-67 labeling index in the intrahepatic cholangiocarcinoma. METHODS: We analyzed 36 cases of intrahepatic cholangiocarcinoma obtained by surgical resection. Expression of p53, Rb, bcl-2 proteins and Ki-67 labeling index were evaluated by immunohistochemical study. RESULTS: Expression of p53 protein was detected in 61.1% (22/36) of cholangiocarcinoma. Rb protein loss and overexpression were observed 27.8% (7/36) and 72.2% (29/36) of cholangiocarcinoma. But bcl-2 protein was not expressed. No significant correlation was found between p53, Rb and bcl-2 protein expression and age, sex, gross type, histologic grade, vascular invasion and lymph node metastases. The Ki-67 labeling index was significantly higher in p53 positive group and Rb overexpression group than in p53 negative group (p<0.01) and Rb loss group (p<0.05). There was a positive correlation between p53 protein and Rb protein expressions, but a negative correlation between Rb protein and bcl-2 protein expressions. CONCLUSIONS: The overexpression of p53 protein and Rb protein may be closely associated with cholangiocarcinogenesis, while bcl-2 has a less crucial role in cholangiocarcinogenesis.