Chromosomal imbalances revealed in primary renal cell carcinomas by comparative genomic hybridization

Renal cell carcinoma (RCC) accounts for approximately 3% of all new cancer cases. Although the classification of RCC is based mainly on histology, this method is not always accurate. We applied comparative genomic hybridization (CGH) to determine genomic alterations in 46 cases of different RCC histological subtypes [10 cases of clear cell RCC (CCRCC), 13 cases of papillary RCC (PRCC), 12 cases of chromophobe RCC (CRCC), 9 cases of Xp11.2 translocation RCC (Xp11.2RCC), 2 cases of undifferentiated RCC (unRCC)], and investigated the relationships between clinical parameters and genomic aberrations. Changes involving one or more regions of the genome were seen in all RCC patients; DNA sequence gains were most frequently (>30%) seen in chromosomes 7q, 16p, and 20q; losses from 1p, 3p, 13q, 14q, and 8p. We conclude CGH is a useful complementary method for differential diagnosis of RCC. Loss of 3p21-25, 15q, and gain of 16p11-13 are relatively particular to CCRCC vs. other types of RCC. Gain of 7p13-22, 8q21-24, and loss of 18q12-ter, 14q13-24, and Xp11-q13/Y are more apparent in PRCC, and gain of 8q21-24 is characteristic of type 2 PRCC vs. type 1 PRCC. Loss of 2q12-32, 10p12-15, and 11p11-15, 13p are characteristic of CRCC, and gain of 3p and loss of 11p11-15 and 13p are significant differentiators between common CRCC and CRCC accompanied by sarcomatous change groups. Gain of Xp11-12 is characteristic of the Xp11.2RCC group. Based on Multivariate Cox regression analysis, aberration in 5 chromosome regions were poor prognostic markers of RCC, and include the gain of chromosome 12p12-ter (P = 0.034, RR = 3.502, 95% CI 1.097-11.182), 12q14-ter (P = 0.002, RR = 5.115, 95% CI 1.847-14.170), 16q21-24 (P = 0.044, RR = 2.629, 95% CI 1.027-6.731), 17p12-ter (P = 0.017, RR = 3.643, 95% CI 1.262-10.512) and the loss of 18q12-23 (P = 0.049, RR = 2.911, 95% CI 1.006-8.425), which may provide clues of new genes involved in RCC tumorigenesis.