DELETION MAPPING ON CHROMOSOME 1P IN WELL-DIFFERENTIATED GASTRIC-CANCER

To define the region on the short arm of chromosome 1 that is thought to include one or more tumour-suppressor genes for gastric cancers, we carried out loss of heterozygosity (LOH) studies in 26 gastric adenoc arcinomas, using three restriction fragment length polymorphism (RFLP) markers and nine microsatellite markers. All tumours were informative with at least one locus; three revealed replication errors (RERs) at multiple microsatellite loci, and interstitial or telomeric allelic de letions were observed in 12 cases. Deletion mapping of these tumours d efined a commonly deleted region between two loci, D1S201 and D1S197, that are 13 cM apart. As two loci within the commonly deleted region, D1S57 (pYNZ2) and D1S62 (pTH154), were mapped respectively to 1p35 and 1p34.3 by fluorescence in situ hybridisation, we conclude that a locu s likely to contain a tumour-suppressor gene for gastric cancer is loc ated within a 13 cM region encompassing these two chromosomal bands.