Characterization of quantitative chromosomal abnormalities in renal cell carcinomas by interphase four-color...

Renal cell carcinomas (RCC) in adults are histologically heterogeneous solid tumors with specific chromosomal abnormality patterns included in the World Health Organization (WHO) classification. To overcome some of the drawbacks of cytogenetic and comparative genomic hybridization (CGH) analyses, we designed a first-generation cytogenetic diagnostic test using four-color fluorescence in situ hybridization (FISH) on interphase nuclei. We selected 51 bacterial artificial chromosome and P1-derived artificial chromosome clones covering 17 chromosomal regions involved in the abnormalities of the adult RCC histologic subtypes. An initial set of probes allowed the identification of clear-cell RCC, papillary RCC, and other RCC on a single slide. A second test allowed the detection of additional chromosomal abnormalities or aberrations specific to chromophobic RCC and oncocytomas. We tested 25 cases of RCC, and the results were in agreement with those of cytogenetic techniques and/or CGH methods. The techniques appeared to be very sensitive, because small tumoral cell clones that were undetected by other cytogenetic methods were identified with this method. It was concluded that the multicolor FISH test was specific and sensitive, easy to perform, and could be part of the investigation process in RCC.