Strong Prognostic Value of Microsatellite Instability in Intestinal Type Non-cardia Gastric Cancer

The clinical role of microsatellite instability (MSI) in gastric cancer (GC) is controversial. A large series of patients submitted to respective surgery for primary GC with a long follow-up time was evaluated. 472 patients with prospectively collected frozen samples of normal mucosa and tumor tissue stored in a biological tissue bank were included. Microsatellite analysis was evaluated using 5 quasi monomorphic mononucleotide repeats (BAT-26, BAT-25, NR-24, NR-21, and NR-27). The presence of MSI in 2 or more loci was classified as MSI-H, whereas all other cases were included in the microsatellite-stable (MSS) group. MSI-H phenotype was found in 111 of 472 patients (23.5 %). MSI-H status was related significantly with older age, female gender, non-cardia location, WHO histotype, non-cardia Lauren intestinal type, and less advanced stages. Cancer-related 5-year survival was significantly higher in MSI-H versus MSS group (67.6 % vs. 35 %, p