Immunohistochemical analysis of p53 and proliferating cell nuclear antigen (PCNA) in bladder cancer: positive immunostaining and radiosensitivity.

BACKGROUND

Preoperative radiation therapy followed by radical cystectomy for invasive bladder cancer has been considered beneficial for selected patients whose tumors display a pronounced initial response to radiotherapy.

METHODS

In order to determine whether overexpression of p53 gene products or proliferating cell nuclear antigen (PCNA) can be used to predict the response of invasive bladder cancer to radiotherapy, an immunohistochemical study of bladder cancers with monoclonal antibodies to p53 or PCNA (PAb 1801 or PC10) was performed. The results of immunostaining of pretreatment biopsy specimens from 60 invasive bladder cancers were analyzed to determine the relationship between labeling for p53 or PCNA and radiosensitivity as determined by histopathological examination of cystectomy specimens obtained after preoperative radiation.

RESULTS

The group with a good response to preoperative radiation therapy had better progression-free rates than did the group with a poor response (P < 0.05). There was no significant difference in radiosensitivity between patients with primary tumors with negative and positive immunostaining for p53. On the other hand, the PCNA labeling index (LI) differed significantly between tumors with poor and good histopathological responses to radiation therapy (P < 0.05).

CONCLUSION

No correlation was found between immunohistochemically detectable alterations of p53 gene products and the radiosensitivity of invasive transitional cell carcinoma of the bladder. However, PCNA immunostaining may be useful for identifying patients for whom preoperative radiation might prove beneficial.