LOSS OF HETEROZYGOSITY FOR CHROMOSOME-11 IN ADENOCARCINOMA OF THE STOMACH

Loss of heterozygosity (LOH) at several chromosomal loci is a common f eature of the malignant progression of human tumors. In the case of ch romosome 11, LOH has been well documented in several types of solid ne oplasms, including gastric carcinoma, suggesting the presence of suppr essor gene(s) at 11p15 and 11q22-23. Little is currently known about t he molecular events occurring during the development of gastric cancer . To define the regions of chromosome 11 involved in gastric cancer pr ogression, we used high-density polymorphic markers to screen for LOH in matched normal and tumor tissue DNA from 60 primary gastric carcino mas. We found that 21% of the tumors showed LOH simultaneously at 11p1 5 and 11q22-23, 41% had LOH at 11p15, and 30% had LOH at 11q22-23. We confirm that the minimal critical area of LOH for 11p15,5 is the appro ximately 2-Mb region between loci D11S1318 and D11S988. However, when we analyzed the pattern of LOH according to the country of origin of t he patient, LOH for 11q22-23 alone was found only in cases from Italy. The minimal critical region of LOH at 11q22-23 is identical to that i dentified for other solid tumors, suggesting that the same putative tu mor suppressor gene(s) contained within this region is involved in the pathogenesis of several common human tumors.