Histologic prognostic factors associated with chromosomal imbalances in a contemporary series of 89 clear cell renal cell carcinomas

Abstract

Clear cell renal cell carcinoma (ccRCC) is the most common type of renal cancer. The aim of this study was to define specific chromosomal imbalances in ccRCC that could be related to clinical or histologic prognostic factors. Tumors and karyotypes of 89 patients who underwent nephrectomy for ccRCC were analyzed from April 2009 to July 2012. The mean number of chromosomal aberrations was significantly higher (7.8; P < .05) in Fuhrman grade 4 (F4) than in F3 (4) and F2 (3.4) cases. The results were similar, considering separately the mean number of chromosomal losses and gains. The F4 cases had a distinct pattern with more frequent losses of chromosomes 9, 13, 14, 18, 21, 22, and Y and gains of chromosome 20. Necrosis was associated with losses of chromosomes 7, 9, 18, and 22; sarcomatoid component, losses of chromosomes 7, 9, and 14 and gains of 20; and T stage, losses of chromosomes 18 and Y. After multivariate analysis, renal fat invasion, renal vein emboli, and microscopic vascular invasion were, respectively, associated with losses of chromosomes 13 and Y, loss of chromosome 13, and loss of chromosome 14 and gains of chromosomes 7 and 20. F4 was independently associated with losses of chromosomes 9 and Y; sarcomatoid component, loss of chromosome 9 and gain of 20; necrosis, loss of chromosome 18; and T stage, loss of chromosome Y. These chromosomal imbalances can be detected routinely by karyotype or fluorescence in situ hybridization analyses to stratify patients for risk of progression.