REGIONAL DNA CONTENT HETEROGENEITY IN WILMS-TUMOR - INCIDENCE AND POTENTIAL CLINICAL RELEVANCE

DNA content (ploidy status and proliferative fraction) was retrospecti vely studied by flow cytometry on archival material from 44 Wilms' tum ors of the kidney to evaluate intratumoral DNA heterogeneity and corre late the findings with clinicopathologic factors and patients' outcome . Analyses of 168 blocks from these neoplasms (average 4 per case) rev ealed diploid DNA in 24 (54.5%) and aneuploid DNA in 20 (45.5%). Thirt een (29.5%) Wilms' tumors demonstrated intratumoral DNA heterogeneity. No statistical correlation between DNA content and age, gender, rumor size, tumor stage, histological subtypes, and clinical outcome was fo und. Significant association, however, was found between DNA ploidy he terogeneity and unfavorable histology, and death due to disease. Our r esults indicate that approximately one third of Wilms' tumors manifest intratumoral heterogeneity and this accounts, at least in part, for t he variable incidence of DNA ploidy reported and may be associated wit h pernicious biological feature.