BIOLOGICAL CHARACTERISTICS OF INVERTED PAPILLOMA OF THE URINARY-BLADDER

Objectives To elucidate the biological characteristics of inverted pap illoma (IF) of the bladder. Materials and methods The immunoreactivity of p53, nuclear DNA content (assessed by ploidy and 2c deviation inde x [2cDI]) and the expression of proliferating cell nuclear antigen (PC NA) in 17 IPs were evaluated using a computer-assisted image analyser and compared with those in 12 superficial transitional cell carcinomas (TCCs), 29 invasive TCCs and one inverted papillary TCC of the bladde r. Results Positive staining for p53 and PCNA and intense staining wit h Feulgen were observed predominantly in the basal layer of the bladde r mucosa. All IPs and most superficial TCCs were diploid, while most i nvasive TCCs were aneuploid, Although the 2cDI and the immunoreactivit ies for PCNA and p53 were significantly lower in IPs than in invasive TCCs, there was no significant difference in these three variables bet ween IPs and superficial TCCs. However, some IPs were more immunoreact ive for p53 than were the superficial TCCs. Conclusions The distributi on of cells with p53 and PCNA immunoreactivity, and with intense Feulg en staining, indicated that TP of the bladder might have high prolifer ative activity and that those IPs with a high immunoreactivity for p53 may be susceptible to malignant transformation.