Deletion mapping of chromosome 11 in carcinoma of the bladder

Deletions of the short arm of chromosome 11 have been identified by both cytogenetic and molecular criteria in bladder and other types of solid tumor, indicating the presence of one or more suppressor loci in this region. To localize the 11p deletion target(s) more precisely and to screen for loss of heterozygosity (LOH) on the long arm of the chromosome, 100 bladder tumors were analyzed for LOH on chromosome 11 using restriction fragment length polymorphisms (RFLPs) and microsatellite markers mapped to both 11p and 11q. Thirty-four tumors were found to have LOH at 1 or more loci. Of these, 17 had LOH restricted to 11p, 13 had LOH of both 11p and 11q, and 4 had LOH of 11q only. Eight tumors showed LOH at all informative loci indicating probable loss of an entire copy of chromosome 11. A common region of deletion was defined on 11p between D11S922 (11p15.5) and D11S569 (11p15.1-15.2). This region does not include the HRAS or WT1 loci (at 11p15.5 and 11p13, respectively). Seventeen tumors had LOH on 11q, 4 of which had LOH on 11q only. The common region of deletion on 11q was between FGF3 and D11S490 (11q13-q23.2). Two tumors showed LOH on both 11p and 11q with a clear region of retention of heterozygosity between, indicating the existence of two deletion targets on chromosome 11.