[Evaluations of protein p53 overexpression in cancer of the bladder: prognostic value]

Management of Transitional Cell Carcinoma (TCC) of the bladder depends on clinicopathological parameters at initial presentation. These criteria are insufficient predictors because of tumor heteterogeneity. Progress in tumor biology suggest that molecular markers may be used to dismember bladder cancer according to their biological behavior. Evidences have accumulated that cancer result from accumulation of molecular defect specially on tumor suppressor genes. In this respect we studied by mean of immunohistochemistry the prognostic value of p53 nuclear overexpression using monoclonal antibody P1801. The study was performed on 114 TTC and 13 normal bladders. Nuclear straining was quantified using an eye piece reticule at magnification 400x. Scoring was determined counting 500 nuclei in 3 to 5 arbitrary fields. Results between stage, grade and percentage of stained nuclei are as follow: TA 0,92-T1 0,144-T2 0,354-T4 0,622-G1 0,105-G2 0,212-G3 0,406. Comparison of mean nuclear straining between group with and without progression indicates a threshold of 16% for p53 nuclear overexpression. Using this limit there is a significant progression free survival rate for the all group (p < 0,0001) and for the group of superficial tumors (p = 0,0007). Multivariate analysis using stepvise logistic regression indicate a p53 prognostic value independent from stage and grade (OR 23,4). This result indicates that p53 overexpression which can be determined on routine preparation has a strong prognostic value and a certain clinical utility.