DNA content in renal cell carcinoma with reference to tumor heterogeneity

DNA content was successfully determined by flow cytometry in 196 tissue samples from 25 renal cell carcinomas. Twelve tumors (48%) were homogeneously diploid/near-diploid, whereas 11 tumors were aneuploid and 2 tumors were polyploid. Cell clones with different DNA content were found in 11 tumors demonstrating a considerable heterogeneity in the non-diploid tumors; 9 of these 11 heterogeneous tumors contained both aneuploid and diploid cell clones. Tumor samples morphologically classified as grade 1 and 2 were 98% diploid and grade 4 samples were 78% aneuploid. No correlation between DNA distribution and morphologic grade was found for grade 3 tumor samples. Tumor proliferation rate, as determined by the fraction of cells in S-phase, was significantly higher in aneuploid samples compared to normal kidney tissue samples and diploid tumor samples.