The Significance of the p53 Protein Overexpression as a Prognostic Marker in Transitional Cell Carcinoma of the Bladder Treated with Radical Cystectomy

Chung, Jin Soo; Kim, Soo Woong; Lee, Sang Eun

Abstract

A gene p53, which is a tumor suppressor gene located on chromosome 17p, regulates cell growth and proliferation, and inactivation of this gene appears to be a common abnormality in many malignant tumors in human. To investigate the prevalence and patterns of p53 protein overexpression and the significance of the p53 protein overexpression as a marker for poor prognosis in transitional cell carcinoma of the bladder which were treated with radical cystectomy, fifty deparaffinized archival specimens from radical cystectomy for transitional cell carcinoma of the bladder were analyzed immunohistochemically to detect overexpression of p53 protein using the mouse monoclonal antibody DO-7 with a standard avidin-biotin immunoperoxidase method. The incidence of p53 expression was 17 of50 (34 per cent) specimens. The p53 expression was associated with histopathologic grade but not with T stage and the status of lymph node involvement. There was no evidence of high recurrence rate, metastasis rate or low survival rate in patients with p53 positive group compared to p53 negative group. But the patients with p53 positive group showed higher T stage and shorter mean survival time than those with p53 negative group. It was not statistically significant. Among many variables evaluated with multivariate analysis, T stage was a significant factor in terms of metastasis, while the status of lymph node involvement was a significant one in terms of survival. In conclusion, the incidence of p53 gene mutation appeared to be higher in invasive and high grade bladder cancer than in superficial and low grade ones. The p53 expression failed to show an unfavorable prognostic factor in transitional cell carcinoma of the bladder treated with radical cystectomy. Prospective studies of large cohorts of specimens are needed to evaluate nuclear overexpression of p53 protein as a prognostic marker in bladder cancer.