VHL gene alterations in Italian patients with isolated renal cell carcinomas.

Clear cell renal cell carcinoma (ccRC) is the most common malignant neoplasm of the kidney and belongs to the few human tumors known to develop from mutations of the VHL tumor suppressor gene. VHL germline mutations are associated with hereditary ccRCs in VHL disease. However, somatic VHL gene defects may also occur in sporadic ccRCs. In this study, we analyzed the frequency and the spectrum of VHL gene alterations in 35 Italian patients with sporadic renal cell carcinoma (RC). Tumor-specific intragenic VHL pathogenic mutations were detected in 38% (11/29) of the ccRC patients and 33% (2/6) of the patients with other types of RC. One novel 18-bp in-tandem duplication and 4 previously unreported nucleotide changes in the VHL gene were described. Microsatellite analysis showed loss of heterozygosity for at least 1 informative marker in 43% (9/21) of the ccRCs and 50% (3/6) of the non-ccRCs; 5 of the 13 tumors (38%) harboring VHL gene alterations also had loss of heterozygosity for at least 1 microsatellite marker. Our results confirm that somatic inactivation of the VHL gene may play a pivotal role in the tumorigenesis of sporadic ccRCs in Italian patients and suggests that mutation analysis of the VHL gene may be helpful for discriminating sporadic, VHL-gene-related ccRCs from those related to VHL disease.