Nuclear deoxyribonucleic acid ploidy of testicular tumors: Peculiar features and clinical significance

To verify the usefulness of testicular DNA ploidy measurement, we tried some approaches to tumorous and nontumorous testes. Separation of paraffin-embedded specimens into single dissociated nuclei was performed by Hedley's technique and nuclei were stained with propidium iodide. Control nontumorous testes were clearly separated into the three-peak type with a high G(2)M percentage and the two-peak type with a low G(2)M percentage. Among testicular tumors, 25% (8 of 32) had a normal DNA diploid pattern, 15.6% (5 of 32) had an increased DNA tetraploid pattern including DNA polyploidy, and 59.4% (19 of 32) were DNA aneuploid. In detail, 26.3% (5 of 19) of seminomas and 23.1% (3 of 13) of nonseminomas were DNA diploid. Interestingly, seminomas showed a variety of DNA histogram profiles. Among DNA aneuploid tumors, the DNA index of a seminoma was significantly higher than that of a nonseminoma. Among patients who received curative orchiectomy, postoperative metastases did not occur in any of the 8 DNA diploid or 5 tetraploid tumors, but did occur in 4 (21.1%) of 19 DNA aneuploid tumors during an at least 6-year follow-up. Clinicopathological findings were not as predictable as DNA ploidy. Flow cytometry appeared to be useful to characterize testicular tumors.