MSH2 and Lynch syndrome: Microsatellite instability (MSI) and/or loss of the mutated protein’s expression by immunohistochemistry (IHC) in the tumors were detected in five patients, who were considered to meet Lynch syndrome GT criteria based on their MSI/mismatch repair-deficient tumor profiles [62], whereas four patients with MSH2 or PMS2 variants had microsatellite stable/indeterminate tumors with retained mismatch repair protein expression.