Immunohistochemical detection of p53 protein in transitional cell carcinoma of the bladder in correlation to DNA ploidy and pathohistological stage and grade.

Abstract

Mutations of p53 gene have been found in a variety of human malignancies; however, the impact of immunohistological detection of p53 expression in the development and progression of TCC of the bladder is still uncertain. In the present study, we investigated the p53 oncoprotein expression and compared the findings to DNA ploidy and pathohistological stage and grade. The study included 147 patients with transitional cell carcinoma of the bladder investigated between February 1981 and September 1994. The average age of the 55 women and 92 men was 67 years (range: 20-71 years). A total of 76 patients (52%) had stage pTa to pT1, 35 (24%) stage pT2, 25 (17%) stage pT3, and 11 (7%) stage pT4 disease. Frozen sections of tumor biopsies obtained by transurethral resection were immunohistochemically stained using the monoclonal antibody clone D0-7 (DAKO), which recognized two different epitopes for mutant and wild-type p53 protein. Tumors expressing p53 in more than 10% of the tumor nuclei were regarded as positive. The DNA ploidy was determined by image analysis. Immunohistochemical detection of p53 expression was found in 84 (57%) of the 147 tumors examined. Positive p53 staining was seen in grade I tumors in 10 to 25%, in grade II tumors 25 to 75%, and in grade III up to 58% of the tumor nuclei. There was a positive correlation between p53 expression and pathological stage (28% in pTa, 73% in pT1-2, and 68% in pT3-4 tumors). There was no appreciable relationship between DNA Ploidy and p53. Although carcinomas with p53 expression had a slight tendency to be more prevalent among higher disease stages and poorly differentiated transitional cell carcinoma, immunohistochemical detection of p53 is not a valuable tool for predicting the outcome of patients with TCC or for identifying subgroups of patients that may be at a higher risk for tumor progression.