[Expression of proliferating cell nuclear antigen in superficial bladder cancer--application to paraffin-embedded tissue sections].

It is important to know the proliferating ability and the malignant potential of each tumor. We studied 56 cases of pTa to pT1 superficial bladder tumors using immunohistochemical staining for proliferating cell nuclear antigen (PCNA), and compared the results with the clinical course of each patient. We obtained the following results. 1) We detected the PCNA positive nuclei in all cases, and the PCNA positive rates varied within a range of 1.1-77.5% with a mean of 34.0%. 2) The PCNA positive rate showed no correlation with age, sex, duration of paraffin-embedded, or pathological stage, but showed a significant correlation with the number of tumors, pathological grade of malignancy, or non-recurrence rate. PCNA positive rate of Grade 1 cases (n = 19, 15.6%: mean) was significantly lower than those of Grade 2 cases (n = 27, 39.9%) or Grade 3 cases (n = 10, 53.1%) (P < 0.01). The recurrence rate of the cases with PCNA positive rates of more than 34% (n = 24) was significantly higher than that of the cases with a PCNA positive rate of less than 34% (n = 32) (P < 0.05). In conclusion, the method of counting the rate of PCNA positive nuclei is considered to be very useful because of its applicability to paraffin-embedded tissue sections and the simple and rapid techniques. Our results in bladder cancer tissues suggest that this method may also be useful for investigating the proliferating ability and the malignant potential of tumors in general.