[Inheritance instability of chromosome 6q in patients with gastric cancer].

OBJECTIVE: To investigate the possible correlation between the microsatellite DNA instability (MSI), loss of heterozygosity (LOH ) on the long arm of chromosome 6 (6q) and the clinicopathologic features in Chinese patients with gastric cancer. METHODS: PCR-SSLP-Silver Stain method was used to detect four loci MSI and LOH in gastric tumor and paired normal control tissues of twenty and seven cases. RESULTS: In our study, the positive of MSI at one or more loci were observed in 16 out of 27 informative individuals (59.2%). 7 cases of 11 informative individuals without MSI were detected to happen the LOH at one or more loci (63.6%). And both MSI and LOH were frequently resulting at loci D6S434 (6q16.3-q21) and D6S404 (6q16.3-q23.2). MSI and LOH occurred in both well-differentiated and poor- differentiated gastric cancers, with a slight tendency of high grade MSI (MSI-H) existing chiefly in well-differentiated gastric cancer. CONCLUSION: The existence of MSI and/or LOH on 6q in 80% gastric carcinoma suggests that the genetic instability of 6q plays an important role in Chinese gastric cancer. The frequency of MSI and LOH has no significant relationship to clinicopathologic features such as age, gender, histological grade of differentiation and stages of tumor. The critical region of allelic deletion on 6q in Chinese gastric cancer is similar to those in other countries, and further confirms the presence of a putative tumor suppressor gene in this region.