DISTAL NEPHRON RENAL TUMORS - MICROSATELLITE ALLELOTYPE

Tumors of varying malignant potential arise from the complex epithelia l lining of the nephron, Although the molecular characteristics of ren al clear cell carcinomas, which arise from the proximal tubule, have b een studied, little is known about tumors that develop from other part s of the renal tubular system, To elucidate common molecular lesions t hat may contribute to the development or progression of nonproximal tu bule renal tumors, we performed a detailed microsatellite allelotype o f lesions thought to arise from the renal collecting duct, Eighteen co llecting duct carcinomas (CDCs) and 13 renal oncocytomas mere studied using highly informative microsatellite markers on all autosomal arms, Loss of heterozygosity (LOH) was identified on multiple chromosomal a rms in CDCs and renal oncocytomas, Microsatellite analysis revealed LO H of Iq in 57% of informative CDCs, LOH was also observed on arms 6p ( 45%), 8p (40%). In renal oncocytomas, LOH of Iq occurred in approximat ely 30% of tumors, but Ip LOH was observed in 57% of informative cases analyzed, High levels of LOH were also observed on arms 8p, 14q, 19q, and 21q in the oncocytomas studied, Loss of chromosomal arm 3p was in frequent in both tumor types, Our results suggest that the molecular e vents that contribute to the development of distal nephron tumors are distinct from those associated with the etiology of proximal tubule re nal cancers.