FISH analysis in chromophobe renal-cell carcinoma

Loss of chromosomes 1, 2, 6, 10, 13, 17, and 21 is a characteristic finding in chromophobe renal-cell carcinoma (ChRCC). Previously, cytogenetic and m olecular genetic techniques were used in demonstrating the chromosomal mono somies in ChRCCs. We performed interphase fluorescent in situ hybridization (FISH) using centromeric probes for chromosomes 1, 2, 6 and 10 on touch im print smears from sir histologically proven ChRCCs. All sir ChRCC tumors sh owed one FISH signal corresponding to one copy number for each of these chr omosomes. The pet-cent cells with one FISH signal ranged from 48-88% (chrom osome 1), 36-89% (chromosome 2), 26-98% (chromosome 6), and 64-99% (chromos ome 10). In addition, 3 of the 6 cases were further studied with centromeri c probes for chromosomes 13, 17, and 21. All three revealed monosomy of the se three chromosomes. We conclude that interphase FISH performed on touch i mprint smears is a relatively simple, rapid, and reliable method for detect ing chromosome abnormalities which are specific for ChRCCs. Diagn. Cytopath ol. 2000;22:3-6.(C) 2000 Wiley-Liss, Inc.