Frequent microsatellite instability and absent hMLH1 expression in solid-type poorly differentiated adenocarcinomas of the stomach

摘要

To clarify clinicopathologic features of microsatellite-unstable solid-type poorly differentiated adenocarcinoma, MSI and expression of hMLH1 were examined in 54 poorly differentiated gastric carcinomas (31 solid-type, 6 nonsolid-type and 17 signet-ring cell carcinomas) as well as clinicopathologic features. Microsatellite instability (MSI) and absent hMLH1 expression were detected in 52% and 58% of solid-type carcinoma, respectively, whereas 17% and 17% in nonsolid-type carcinoma and 12% and 18% in signet-ring cell carcinoma, respectively. MSI-positive solid-type carcinomas were significantly related with older age, women, lower third location, presence of concordant glandular component, and absent hMLH1 expression. MSI-positive solid-type poorly differentiated adenocarcinoma has peculiar clinicopathologic characteristics. Moreover, MSI with absent hMLH1 expression may play an important role on the development of the solid-type carcinoma in the elderly, especially in the women.