[Expression of proliferating cell nuclear antigen (PCNA) in renal cell carcinoma]

The objective of this study is to evaluate the relationship among PCNA positive ratio, pathological findings, nuclear DNA contents, and prognosis in renal cell carcinoma. Immunohistochemical analysis using the monoclonal antibody of PCNA were performed on a total number of 151 formalin-fixed paraffin-embedded samples (1-7 samples with a mean of 3.8) from 40 renal cell carcinomas. The percentage of PCNA positive cancer cells to the total amount of cancer cells was expressed as labeling index (LI; %). By means of flow cytometry we analysed nuclear DNA contents from the same samples.

1) LIes in pathological grades were 2.79 +/- 3.33% (mean +/- SD) for grade 1 (n = 16), 5.63 +/- 4.08% for grade 2 (n = 20), and 9.95 +/- 4.59% for grade 3 (n = 4). There was significant difference between grade 1 and grade 3 (p < 0.05). 2) LIes in pathological stage were 3.22 +/- 3.05% for pT2 (n = 22) and 7.01 +/- 4.99% for pT3 and pT4 (n = 18) (p < 0.05). 3) There was no significant correlation between LI and lymph node involvement. And there was no significant correlation between LI and distant metastasis, either. 4) LIes in nuclear DNA contents were 2.41 +/- 3.14% for DNA diploid (n = 17) and 6.80 +/- 4.29% for DNA aneuploid (n = 23) (p < 0.05). 5) It was suggested that LI was shown to vary according to the parts in a given tumor examined in parallel with tumor heterogeneity of nuclear DNA content. 6) The 5-year cause-specific survival rate of the patients with LI > or = 5.0% (n = 15) was 40%, while that with LI < 5.0% was 74% (n = 25) (p < 0.05).

These findings suggest that LI, which was determined by immunohistochemical analysis using PCNA antibody indicates a growth potential of renal cell carcinoma and is available for estimating malignant potential.