Unusual chromosome patterns of renal cell carcinomas common to two brothers

In this study, we describe two renal cell carcinomas (RCC) that occurred at the same time in two brothers, yielding information on the carcinogenic process. We used flow cytometry (FCM) to evaluate nuclear DNA content, and performed cytogenetic analysis. We also carried out fluorescence in situ hybridization (FISH) with a panel of centromeric probes for chromosomes 3, 7, 8, 9, 12, 17, 20, and Y in interphase cells. Flow cytometry analysis revealed diploid histograms in the tumor and "nonmalignant" samples of patient 1, while an aneuploid cell subpopulation was found in the tumor and "nonmalignant" samples of patient 2. Tumor samples from the two brothers were studied by FISH, and had common numerical chromosome aberrations: trisomy of chromosomes 3 and 7, and monosomy and trisomy of chromosomes 9 and 17. Moreover, in normal samples from both brothers, we found monosomy 9, and in a normal sample from patient 1, monosomy 17. Cytogenetic analysis revealed trisomy 3 in some cells grown from normal kidney tissue of each brother. The identification of the same chromosome alterations in both brothers appears to provide evidence of an unusual process of carcinogenesis, probably due to a common genetic basis.