What is MSI Low?

MSI low (MSI-L) refers to the condition where there is instability at only one microsatellite site. According to a reference from January 13, 2020, instability in one site is classified as low microsatellite instability (MSI-L). In contrast, instability in two or more sites is classified as high microsatellite instability (MSI-H), and the instability of all five sites is classified as microsatellite instability (MSS).