microsatellite instability
(MY-kroh-SA-teh-lite in-stuh-BIH-lih-tee)
A characteristic of cells that contain an abnormality in DNA mismatch repair. The presence of microsatellite instability can be a marker of a germline pathogenic variant in one of the DNA mismatch repair genes, as in the case of Lynch syndrome. Microsatellite instability can also occur sporadically. Also called MSI.