Delineation and physical separation of novel translocation breakpoints on chromosome 1p in two genetically closely associated childhood tumors

Sporadic childhood tumors associated with Beckwith-Wiedemann syndrome (BWS) all show abnormalities of the same region on chromosome 11. In addition to chromosome 11, other chromosome regions are affected in some of these tumo r types. In this study we analyzed the region on chromosome Ip involved in the etiology of BWS-associated tumors, Wilms tumor, rhabdomyosarcoma, and h epatoblastoma. For this purpose we determined the location of two novel tra nslocation breakpoints in this chromosome region in cells from a Wilms tumo r and cells from a rhabdomyosarcoma. We constructed a map of the region and found that both breakpoints are separated by at least 875 kb. We identifie d a PAC clone which crosses the rhabdomyosarcoma breakpoint and found sever al exons within this clone. We established that this breakpoint is located proximal to the PAX7 gene and, therefore, identified a new region involved in the etiology of rhabdomyosarcomas. Copyright (C) 2000 S. Karger AG, Base l.