Correlation between p53 over expression and response to bacillus Calmette-Guerin therapy in a high risk select...

The aim of this study was to determine if p53 status, assessed before intravesical bacillus Calmette-Guerin (BCG) therapy, can predict clinical outcome in a high risk population of patients with stage T1, grade G3 bladder cancer and if it can be used to select patients responsive to therapy.

After complete transurethral resection 35 patients with T1G3 bladder carcinoma received 6 weekly instillations of BCG and nonresponsive patients received a second course. After treatment cystoscopy and randomized biopsies of the bladder mucosa were performed. Pathologists had sufficient material to perform immunomarking in 25 cases using the peroxidase-antiperoxidase technique with antiprotein monoclonal antibody p53. The results were expressed in percentage of marked nuclei. We established 5% increment thresholds from 0 to 60%. Contingent tables were established, and chi-square and Fisher's exact test were performed for each 5% threshold.

Median followup was 51.3 months (range 25 to 144). Of the 25 patients 8 (32%) did not respond to BCG therapy and 17 (68%) did. Immunomarkings were not statistically different between BCG responsive and nonresponsive patients for 0, 5, 10, 20, 35, 40, 45, 55 and 65 thresholds. Chi-square and Fisher's exact test were 0.91 and 0.83, 0.40 and 0.20, 0.58 and 0.29, 0.96 and 0.81, 0.80 and 0.88, 0.67 and 0.73, 0.91 and 0.83, 0.80 and 0.38, 0.69 and 0.32, respectively.

Our results indicate that the percentage of p53 immunomarked cell cannot currently be used to predict clinical response to BCG therapy and, therefore, p53 over expression is not a viable indicator of T1G3 recurrence when using this treatment.