Significance of p53 Protein Overexpression in Gallbladder Carcinoma

Park, Yong Hyun; Kim, Woo Ho; Kim, Sun Whe; Han, Sang Uk; Her, Kyu Hee

Abstract

BACKGROUND AND AIMS: Mutation of the p53 tumor suppressor gene appears to be an important event in tumor development and progression. Overexpression of the p53 gene product has been widely studied in a variety of neoplasms.
METHODS
Immunohistochemical staining was performed on formalin fixed, paraffin embedded histological sections with an anti-human p53 monoclonal antibody (Vector, DO-7) using fifty-two gallbladder carcinomas and thirty two dysplasias.
RESULTS
Overexpression of p53 protein was found in 34.6% of invasive carcinomas and 15.6% of dysplasias. Normal epithelium, obtained from all the cases, did not express p53 protein. In addition there was no p53 positive metastatic lymph nodes whose primary tumors were p53 negative. Overexpression of p53 was significantly correlated with lymph node involvement as well as stage of the tumors. Five year survival rate of patients with p53-negative tumors was 46.8%, whereas that of patients with p53-positive tumors was 18.8%.
CONCLUSIONS
The progressively increasing incidence of p53 protein overexpression observed from premalignant lesions to invasive tumors supports the view that p53 gene mutations may have a role in the carcinogenesis of gallbladder carcinomas. The fact that p53 protein overexpression was more prevalent in more advanced tumors and in metastatic lymph nodes means that p53 mutation may contribute to the progression of the tumor. Further study is needed to evaluate the significance of p53 as a prognostic factor.