Clinical Implications of Microsatellite Instability in Early Gastric Cancer

Purpose We aimed to evaluate the clinical characteristics of microsatellite instability in early gastric cancer. Materials and Methods The microsatellite instability status of resected early gastric tumors was evaluated using two mononucleotide repeat markers (BAT25 and BAT26) and three dinucleotide repeat markers (D5S346, D2S123, and D17S250). Tumors with instability in two or more markers were defined as microsatellite instability-high (MSI-H) and others were classified as microsatellite stable (MSS). Results Overall, 1,156 tumors were included in the analysis, with 85 (7.4%) classified as MSI-H compared with MSS tumors. For MSI-H tumors, there was a significant correlation with the female sex, older age, tumor location in the lower gastric body, intestinal histology, lymphovascular invasion (LVI), and submucosal invasion (P