PCNA and p53 in urinary bladder cancer: correlation with histological findings and prognosis

This study aimed to immunohistochemically examine the expression of proliferating cell nuclear antigens (PCNA) and p53 protein in transitional cell carcinomas (TCC) of the urinary bladder, and to investigate possible correlations of this expression with the tumor grade or stage, tumor recurrence, and prognosis of the disease.

The immunohistochemical status of the PCNA and p53 proteins were determined on paraffin-embedded sections from 128 patients with TCC of the urinary bladder, using PC-10 and DO7 as the primary antibodies. Positive stainings were represented by scores (Labeling Index; LI, %) calculated as the percent of positive cells among all neoplastic cells counted. The findings were compared to the patients' histopathological features. Patients who underwent transurethral resection were divided into groups with "low" and "high" scores for PCNA and p53, respectively, and the tumor recurrence rate was compared among the groups. Patients who underwent total cystectomy were similarly divided into "low" and "high" score groups, and survival rates of the groups were compared.

PCNA expression was observed in 66 of 128 patients (51.6%), with a mean labeling index of 26.6%. Overexpression of p53 was observed in 65 of 128 patients (50.8%), with a mean labeling index of 35.3%. There were significant correlations of the PCNA and p53 indices with both histological grade and stage of the tumor. In the TUR group, there were no statistically significant differences in recurrence rate between the groups with high or low scores for either PCNA or p53. In the total cystectomy group, there was a significant correlation between survival rate and positive staining for PCNA, but not for p53. The relationship between 2 parameters, PCNA and p53 scores, was not significant (linear correlation coefficient, r = 0.67).

PCNA and p53 status in transitional cell carcinomas of the urinary bladder is related to the histopathological findings. We also suggest that immunohistochemical staining for PCNA provides significant clinical information which may be useful in the initial selection of therapy. However, overexpression of p53 does not appear to represent an independent prognostic marker in bladder tumors.