Abstract: Objective : In order to define the common deleted region linked to primary gas-tric carcinomas in Chinese loss of heterozygosity(LOH) frequency of human chromosome 7q and its clinical significance was investigated. Methods : A set of 9 microsatellite markers on 7q with an average marker density of 10cM were used to examine matched tumor and non-tumor DNAs from 70 patients with primary gastric carcinoma for LOH by multi-PCR amplification. The PCR prod-ucts were separated by electrophoresis in polyacrylamide gel. Genescan and Genotyper softwares were used to analysis LOH. Results : LOH at any locus on 7q occurred in 34.3% (24/70) of the tumors. Among them, LOH at D7S486 and D7S798 were Higher, 24.0% (12/50) and 19.2% (5/ 26),respectively. The frequency of LOH at any locus on 7q was obviously higher and higher with the the rising of clinical stage, P<0.05. The frequency of LOH at D7S486 in cases with lymph node metastasis was obviously higher than that in cases with non-lymph node metastasis,P=0.015. Conclusion : The higher incidence of LOH at D7S486 and D7S798 in primary gastric carcinoma suggests that there might be a potential TSG involved in the progression of gastric carcinoma.