FLOW CYTOMETRIC ANALYSIS OF DNA PLOIDY IN 62 PATIENTS WITH WILMS-TUMOR

Flow cytometric analysis of DNA ploidy was done on nuclei extracted from paraffin-embedded tissue blocks from 62 patients with Wilms' tumor, the largest series reported to date. Thirty-eight tumors were aneuploid and 24 were diploid; there were no tetraploids. Sixty-seven percent of the diploids and 44.7% of the aneuploids survived; the difference was statistically significant (P < 0.01). The 2 congenital mesoblastic nephromas were diploid; the only 2 adult patients were aneuploid. Aneuploids comprised 75% of those presenting in stage III/IV and 75% of the anaplastic tumors. Genetic heterogeneity, never before reported in Wilms' tumor, was found in 2 patients. Aneuploidy was an ominous prognostic factor, particularly when combined with tumor stage and histological grade.