Chromosome bands Ip35-36 contain two distinct neuroblastoma tumor suppressor loci, one of which is imprinted

A previous loss of heterozygosity (LOH) study of a series of 91 neuroblasto mas suggested that the 1p35-36 region encodes at least two tumor suppressor genes (TSGs) of importance in neuroblastoma development. Here we present t he results of a study including 205 neuroblastomas that were analyzed for L OH at chromosome 1 and MYCN amplification. The results corroborate the exis tence of two TSGs on 1p. Distinct 1p loci seem to be involved in MYCN singl e copy vs. MYCN amplified neuroblastoma, as these tumors display a differen t type of shortest region of overlap (SRO). About 15% of MYCN single copy n euroblastomas show 1p deletions of variable length with an SRO of 47 cR at 1p36.3. The lost alleles are preferentially of maternal origin (P = 0.0002) , suggesting parental imprinting of the locus. MYCN amplified neuroblastoma s have a contrasting pattern of 1p loss. These tumors display much larger d eletions of at least 89 cR comprising the region from 1p36.1 to the telomer e. LOH of 1p is detected in 86% of the cases. The lost alleles are of rando m parental origin, suggesting inactivation of a non-imprinted TSG. (C) 2001 Wiley-Liss, Inc.