Background: Proliferative potential of testicular tumor was assessed by immunohistochemistry using anti-proliferating cell nuclear antigen (PCNA) monoclonal antibody and silver staining of argyrophilic nucleolar organizer region (AgNOR), and the results were compared with clinical course.
Methods: Fourty-five patients with testicular tumor and 10 normal testicles were investigated. All specimens were fixed with 10% buffered formaliun within 24 hours. The interval between patient's recognition of testicular swelling for the first time and the date for operation was designated as M (months), and the specimen weight was designated as g (gram). Growth rate of the primary tumor was estimated roughly by g/M.
Results: PCNA positive rates in seminomas, non-seminomas and normal testes were 70.5 +/- 19.1% (mean +/- S.D.), 80.4 +/- 10.5% and 17.7 +/- 7.8%, respectively. PCNA positive rate in stage I seminoma (64.4 +/- 19.9%) was significantly lower than stage II and III seminoma (83.6 +/- 7.3%) (p < 0.05), but not significant between stage I non-seminoma and stage II, III non-seminoma. The mean numbers of AgNOR per nucleus in seminomas, non-seminomas and normal testes were 8.09 +/- 1.35 (mean +/- S.D.), 6.89 +/- 1.43, 4.18 +/- 1.60, respectively and significantly higher in testicular tumors than normal testes. There were, however, no significant difference between their clinical stages. Logarithmic significant correlation was observed between PCNA positive rate and the growth rate in primary lesion, but no correlation was found between mean number of AgNOR per nuclei and the growth rate. Of the 10 patients with stage I non-seminomas received surveillance policy, four relapsed. Of the 10 patients, 4 of the 6 patients with higher than 75% PCNA positive rate relapsed, whereas, none of the 4 patients with lower than 75% PCNA positive rate relapsed. There were no significant correlation between PCNA positive rate and number of AgNOR.
Conclusion: PCNA is more accurate indicator of growth potential in testicular tumor than AgNOR and may predict recurrence in stage I non-seminomatous testicular tumor patients followed by surveillance policy.