[Tumor heterogeneity of renal cell carcinoma as analyzed by flow cytometry]

DNA content in renal cell carcinoma was investigated to examine the tumor heterogeneity and was correlated with their morphologic grades. A total number of 147 paraffin-embedded samples (2-6 samples with a mean of 5) from 30 tumors were analyzed by flow cytometry. DNA aneuploid patterns were demonstrated in 5 of 9 grade 1 tumors (56%), 15 of 18 grade 2 tumors (83%) and 3 of all grade 3 tumors (100%), while aneuploid DNA histograms were exhibited in 20 of 57 grade 1 samples (35%), 45 of 81 grade 2 samples (56%) and 8 of 9 grade 3 samples (89%). DNA aneuploid patterns were demonstrated more significantly in grade 2 and 3 samples than in grade 1 samples (p less than 0.02 and p less than 0.01, respectively). Consequently, 73 samples (50%) showed DNA aneuploid patterns and 74 samples exhibited DNA diploid patterns. Eleven tumors (37%) showed homogeneous DNA ploidy patterns (7 tumors were diploid and 4 tumors were aneuploid only), while 19 tumors (63%) showed DNA heterogeneity, 17 of these 19 tumors demonstrating diploid as well as aneuploid samples. DNA heterogeneity was not found when the tumor samples examined were fewer than 3 samples. However, 19 of 25 tumors (76%) in which more than 4 samples were examined showed DNA heterogeneity, the incidence of which tended to be increased with upgrading of the tumor--3 of 9 (33%) in grade 1 tumors, 13 of 18 (72%) in grade 2 tumors and 3 of all (100%) in grade 3 tumors.(ABSTRACT TRUNCATED AT 250 WORDS)