Chromosome aberrations in renal tumors detected by fluorescence in situ hybridization

The aim of this study was to investigate the relationship between chromosome aberrations detected by fluorescence in situ hybridization (FISH) and tumor grade, stage, venous involvement, and DNA ploidy status in 18 renal tumors. Using FISH with chromosome-specific DNA probes, the copy number of pericentromeric sequences on chromosomes 3, 7, 9, and 17 was detected within interphase nuclei in touch preparations from tumor specimens. Monosomy for chromosome 3 was detected in seven of 9 DNA diploid tumors, whereas all DNA aneuploid tumors demonstrated trisomy or tetrasomy for chromosome 7. Moreover, monosomy for chromosome 3 was more frequently shown in the diploid and low-stage tumors than in the aneuploid and high-stage tumors. The percentage of hyperdiploid cells significantly correlated with DNA ploidy status in the case of chromosomes 3 and 7 (p = 0.030, p = 0.007, respectively). The percentage of hyperdiploid cells for chromosome 3 had borderline significance with tumor stage. On the other hand, the percentage of diploid cells for chromosome 17 was significantly correlated with DNA ploidy status and tumor stage (p = 0.030, p = 0.027, respectively). Moreover, the percentage of diploid cells for chromosome 7 in renal cell carcinoma (RCC) with venous involvement was significantly lower than those without venous involvement (p = 0.023). These results suggest that the incidence of chromosomal aberrations detected by FISH is more frequent than the chromosomal aneuploidy reported previously by conventional cytogenetics. Therefore, loss of chromosome 3 may be associated with an early event in RCC carcinogenesis. Gain of chromosomes 3 and 7 is correlated with tumor progression as well as gain and loss of chromosome 17. Study of the chromosomal aberrations may provide a greater understanding of tumor carcinogenesis and progression in RCC.