Advances in the effect of microsatellite instability on treatment of gastric cancer

Microsatellite instability (MSI) refers to the abnormal occur of DNA mismatch repair function (MMR), and the replication errors of microsatellites cannot be corrected. The accumulation of replication errors leads to change of the length or base composition of the microsatellite. There are 8%-25% of gastric cancer patients presenting MSI. The prognosis of microsatellite instability-high (MSI-H) gastric cancer patients is relatively better. However, compared with microsatellite stability (MSS) gastric cancer patients, MSI-H patients may not benefit from perioperative chemotherapy in survival. In some patients with advanced MSI-H gastric cancer, the effect of immunotherapy improve survival is better than chemotherapy. There are a few MSI-H patients in the past retrospective researches and that whether MSI is a negative predictor for perioperative chemotherapy effect is unknown. This paper reviews progress in impacts of MSI on treatment of gastric cancer in resent years.