Allelic deletions in renal tumors: histopathological correlations

Allelic loss on the short arm of chromosome 3 (3p) is considered to be one of the early detectable events in the pathogenesis of renal cell carcinoma (RCC). Conflicting reports, however, suggest that this event may be absent in some renal tumors. The present study attempts to further define subgroups of renal tumors associated with 3p deletions. In addition, we have also attempted to identify late genetic events associated with tumorigenesis and tumor progression. Eighty-two primary renal tumors (69 RCC and 13 oncocytic tumors) were analyzed by restriction fragment length polymorphism analysis directed at chromosomes 3, 11p, 17p, and 18q. Results were correlated with histopathological information. Deletions of 3p were seen in nonpapillary RCC of all cell types, but were absent in oncocytic and most papillary tumors. Among the 60 nonpapillary RCC, significant correlations were seen between deletion of 17p and tumor grade (P = 0.037), P stage (P = 0.027), and nodal metastases (P = 0.042). We therefore conclude that 3p deletions, although not specific to any cell type or histological pattern of RCC, are seen in a majority of clear cell nonpapillary RCC but are absent in oncocytic and most papillary tumors. Additional allelic losses on chromosome 17p are associated with advanced disease and, therefore, may be related to tumor progression. Further studies on larger series of patients with extended follow-up will be necessary to investigate the prognostic value of molecular genetic markers in RCC.