Use of fish analysis for diagnosis of renal cell carcinoma subtypes

Background: Cytogenetic and molecular genetic techniques have been used in demonstrating the chromosomal abnormalities which characterize specific sub types of renal cell carcinoma (RCC). The aim of this study was to determine the efficiency of fluorescent in situ hybridization (FISH) technique in ch aracterizing various subtypes of RCC based on the presence of specific chro mosome abnormalities found in each RCC subtype. Materials and Methods: FISH was performed on touch imprint smears from eigh t renal cell carcinomas histologically confirmed by established criteria. R esults: In four tumors with histologic features of chromophobe renal cell c arcinoma (ChRCC), interphase FISH was performed using centromeric probes fo r chromosomes 1, 2, 6, 10, 12, 17 and 21. All four ChRCC tumors showed one FISH signal corresponding to one copy number for each of these chromosomes. Two papillary RCCs included in this study showed trisomy 7 and 17, and los s of chromosome Y, using the corresponding chromosome centromeric probes. S imilarly, we tested two clear cell RCCs for chromosome 3 short arm deletion with DNA probe 3p21.3. Both tumors showed loss of 3p21.3 signal. Conclusion: We conclude that interphase FISH performed on touch imprint sme ars is a relatively simple, rapid and reliable method for detecting chromos ome abnormalities which are specific for various subtypes of RCC.