Prognostic value of Ki-67 antigen and p53 protein in urinary bladder cancer: immunohistochemical analysis of radical cystectomy specimens.

OBJECTIVE

To investigate the role of tumour proliferation and p53 expression as a marker of survival in patients with urinary bladder cancer who undergo radical cystectomy.

PATIENTS AND METHODS

Samples were obtained from 31 patients (29 men and two women, mean age 66.0 years, range 46-80) with transitional cell carcinoma of the bladder who underwent radical cystectomy. The 31 formalin-fixed radical cystectomy specimens were stained immunohistochemically for Ki-67 antigen and p53 protein using MIB1 and p53 antibodies, respectively, and the results correlated with tumour grade, stages and prognosis.

RESULTS

The Ki-67 index was significantly greater in high-grade tumours and in those overexpressing p53 (> 20% positive nuclei). Patients whose tumour samples had a high Ki-67 index (> 32%) had a significantly worse prognosis than those with a lower index (P < 0.01). There was a similar correlation between Ki-67 index and prognosis in high-risk patients (grade 3 and pT3-4; P < 0.05). Although the associations between tumour grade, stage and p53 expression were not statistically significant, patients whose tumour samples overexpressed p53 had a lower survival rate (P < 0.05). No patients with tumours having a low Ki-67 and low p53 index (n = 14) died of urinary bladder cancer during the follow-up.

CONCLUSION

These results suggest that immunohistochemical analyses for Ki-67 and p53 are useful prognostic indicators in patients with urinary bladder cancer who undergo radical cystectomy; the prognostic role of these markers was particularly important in high-risk (grade 3 and pT3-4) patients.