Overexpression of p53 protein and its significance for recurrent progressive bladder tumours

To determine the prognostic value of the overexpression of p53 protein as determined by immunohistochemistry in recurrent progressive transitional cell carcinomas of the bladder.

A total of 222 tumours from 86 patients with recurrent disease, 20 from patients with no evidence of recurrence after resection of initial tumour and 11 normal bladder (controls) were investigated. Using a microwave technique to expose antigens, formalin-fixed sections were immunohistochemically stained for p53 using a polyclonal antiserum. Two independent observers scored the sections for evidence of overexpression of p53.

Of 86 patients with recurrent disease, 51 demonstrated overexpression of p53 protein, as did six of 20 patients with non-recurrent disease. Overexpression was not linked to recurrence (P = 0.5) but was related to worsening histological stage (P < 0.01) and increasing grade (P < 0.01). Regression analysis showed that overexpression of p53 for the primary tumour was not of predictive prognostic value for death from bladder cancer, time to progression or time to recurrence. Tumour grade was the only variable of prognostic value in all the statistical models. Patients with overexpression of p53 showed no reduction in overall survival.

These findings suggest that overexpression of p53, as determined immunohistochemically, appears to have no predictive prognostic value over stage and grade in bladder tumours.