Immunohistochemistry of p53 protein in transitional-cell carcinoma of the bladder using an image analyzer

The p53 protein is known to be the product of the tumor suppressor gene p53. To elucidate the biological characteristics of p53 protein in transitional-cell carcinoma (TCC) of the bladder, the positive rate (PR) and positive intensity (PI) of p53 immunostaining in 72 TCCs of the bladder were quantified and compared with clinicopathological findings, prognosis and expression of proliferating-cell nuclear antigen (PCNA). The immunoreactivity for p53 and PCNA was evaluated using the CAS 200 Image Analyzer (Cell Analysis System, Elmhurst, Ill., USA). Intense immunoreactivity for p53 protein was observed not only near the basal cell layer but also at the invasive border. Both PR and PI of p53 were significantly correlated with histological grade (p < 0.05 and P < 0.02, respectively), histological stage (p < 0.02 and p < 0.02, respectively). Both PR and PI of p53 were significantly higher in patients who died of bladder cancer and in patients who developed metastatic progression. Using a univariate analysis, the survival was significantly short in subjects with high PR (> 40%) or high PI (> 70%) of p53 (p < 0.01 in both cases). However, using a multivariate analysis, the prognostic value of p53 immunoreactivity was not superior to histological stage. These findings suggested that, although p53 immunoreactivity appears to be related to proliferative activity in TCCs of the bladder, the prognostic relevance of p53 immunoreactivity was rather limited when evaluating the biological attitude of individual TCC of the bladder.