Evaluation of p53 protein overexpression, ki67 proliferative activity and mitotic index as markers of tumour recurrence in superficial transitional cell carcinoma of the bladder

Objectives: To confirm the interrelationship between p53, ki67, mitotic ind ex with others known prognostic factors such us stage, grade, multifocality , tumour size, history of recurrence in transitional cell carcinoma (TCC) o f the bladder and to determine the prognostic impact of p53, Ki67 and mitot ic index in predicting recurrence in superficial bladder cancer. Methods: Two hundred and fourteen patients with apparently superficial TCC of the bladder underwent TURBT and the 192 histologically Ta-T1 were divide d into 104 primary lesions (group 1, mean follow-up 26 months) and 88 recur rent tumours (group 2, mean follow-up 28 months). Data concerning focality, tumour size, number of recurrences and recurrence-free survival were consi dered in each patients. All samples were immunohistochemically stained with p53 and Ki67 monoclonal antibodies. Mitotic index (MI) was calculated on h aematoxylin and eosin stained sections. Results: Recurrence-free survival was significantly lower in superficial re current tumours (group 2) compared with primary tumours (group 1). P53 stai ning was correlated with grade and stage for both 5 and 20% positivity thre sholds. Ki67 and MI were significantly different over strata defined by sta ge, grade and focality in both patients groups but only Ki67 showed a corre lation with p53 status. Recurrence-free survival could not be predicted eit her by p53 status or MI. A 20% cut-off level of Ki67 staining resulted a go od predictor of recurrence in group 1 Ta-T1/G1-G2 tumours (p = 0.03). Only Ki67 and multifocality were found to be independent prognostic factors of r ecurrence in multivariate analysis. Stratifying Ta-T1/G1-G2 patients accord ing to these variables, Ki67 provided a useful tool to predict early recurr ence in monofocal lesions from both groups. Conclusions: P53 and MI despite a fairly good correlation with traditional prognostic factors in bladder TCC seem to play no role in the prediction of tumoural recurrence. A Ki67 index over 20% predicts those single well-diff erentiated (Ta-T1/G1-G2) tumours which are likely to recur within one year of treatment Copyright (C) 2000 S. Karger AG, Basel.