Definition and refinement of chromosome 8p regions of loss of heterozygosity in gastric cancer.

Loss of heterozygosity at several chromosomal loci is a common feature of the malignant progression of human tumors. These regions are thought to harbor one or more putative tumor suppressor gene(s) playing a role in tumor development. Allelic losses on the short arm of chromosome 8 (8p) have been reported as frequent events in several cancers, and three commonly deleted regions have been defined at 8p11.2-12, 8p21-22, and 8p23.1. To evaluate the possible involvement of these regions in gastric cancer, we used eight microsatellite markers to perform an extensive analysis of allele loss at 8p21-22 in 52 cases of primary gastric adenocarcinoma. We found that 44% of tumors showed allelic loss for at least one marker at 8p21-22. The critical region of loss was found to be between markers LPL and D8S258, which displayed loss of heterozygosity in 39% and 33% of cases, respectively. This region is centromeric to the LPL locus and centered on the D8S258 locus. We conclude that 8p22 deletion is a frequent event in gastric cancer and suggest the presence of a putative tumor suppressor gene near the D8S258 locus. Initial steps were taken toward the identification of this gene, which is likely to play an important role in the pathogenesis of gastric cancer and of other tumors as well.