Heterogeneity and progression of renal cell carcinomas as revealed by DNA cytofluorometry and the significance of the presence of polyploid cells.

With special attention to the presence of polyploid cells, we examined heterogeneity and progression of renal cell carcinomas. We separated 116 blocks from 51 tumors into several specimens according to the histologic findings, and analyzed their DNA ploidy patterns. Thirty-one tumors (61%) were aneuploid, 29 of which showed intratumoral DNA ploidy heterogeneity. Diploid cell lines were observed in 47 tumors (92%). Polyploid cells in the diploid component were more frequently found in tumors with mixed diploid and aneuploid patterns than in the purely diploid tumors. Of the diploid cases, higher stage cases tended to have a higher incidence of polyploid cells than the lower stage cases. The incidence of aneuploid cases and DNA heterogeneity became greater as the tumors progressed. Aneuploid cases had a poorer outcome than did the diploid cases. If diploid cases with polyploid cells were classified as aneuploid cases, the difference in the survival rate between the diploid and aneuploid cases became more significant. Diploid renal cell carcinomas with polyploid cells may be an intermediate stage between diploidy and aneuploidy. Analyzing renal cell carcinomas for the presence of polyploid cells is useful for differentiating diploidy, which is actually aneuploid, from pure diploidy.