Microsatellite instability (MSI) is a form of genetic instability present in virtually all tumors from patients with hereditary nonpolyposis colon cancer and a subset of various sporadic tumors, including colorectal and gastric cancers. Transforming g...
Microsatellite instability (MSI) is a form of genetic instability present in virtually all tumors from patients with hereditary nonpolyposis colon cancer and a subset of various sporadic tumors, including colorectal and gastric cancers. Transforming growth factor-beta receptor 2 (TGFBR2) mutations in MSI-positive cancer cell lines may partially inactivate TGF-$\beta$-induced growth inhibition. The aim of this study was to investigate whether MSI and TGFBR2 gene mutations contribute to the progression from gastric adenoma to cancer in multi step gastric carcinogenesis. MSIs were analyzed using 5 micro satellite markers and a frame shift mutation in poly(A)10 within the TGFBR2 gene in 50 gastric adenomas and 88 gastric cancer specimens. One (2.0%) of 50 gastric adenomas and 22 (25.0%) of 88 gastric cancers were MSI-positive. TGFBR2 frame shift mutations were found in 9 gastric cancers, but not in adenoma. All cases with the TGFBR2 frameshift mutation showed high-frequency MSIs. These results suggest that MSIs may occur in the development of gastric cancers, but not in adenomas less than 2 cm, and the TGFBR2 gene may be a target of genomic instability in MSI gastric carcinogenesis.