Microsatellite allelotyping differentiates chromophobe renal cell carcinomas from renal oncocytomas and identifies new genetic changes

Aims: The diagnosis of renal oncocytomas (ROs) and chromophobe renal cell carcinomas (RCCs) based on histological features is often uncertain. To assess the value of genetic analysis in their differential diagnosis we analysed 27 ROs and 21 chromophobe RCCs by microsatellite allelotyping. Methods and results: Markers at the short and long arms of chromosomes specifically involved in the genetic changes of the four main types of renal cancers were selected. Allelic changes were identified by automated sequencing. Allelic changes at chromosome 1p occurred in 8/26 (31%) and at chromosome 14q in 4/27 (15%) ROs. Loss of heterozygosity (LOH) at chromosomes 1, 2, 6, 10, 13, 17 and 21 were seen in 90%, 90%, 96%, 86%, 85%, 90% and 72% of the chromophobe RCCs, respectively. Alterations of at least three of these chromosomal sites were detected in each chromophobe RCC. In addition, we found recurrent LOH at chromosomes 9p23 (43%), 18q22 (30%), 5q22 (28%) and 8p (28%) in chromophobe RCCs. Conclusions: Chromophobe RCCs can be differentiated from ROs by analysing specific chromosomal regions with microsatellites.