MSH6 and cancer: We collected multiregion WES data after MSH6 IHC from 49 LCM regions (29 MSH6-proficient and 20 MSH6-deficient regions) from 22 MMRd tumors, including 11 MMRd tumors with heterogeneous MSH6 loss, and a control group of 11 MMRd MSH6-proficient cancers.