MRC1 and cancer: MMR protein loss has been shown to be present in 7% of all UUT cancer cases and 30% in LS-related UC of the UUT, in this cohort of patients with UUT urothelial cancers and verified loss of mismatch repair protein expression, up to 86% were affected in loss of MSH2 and MSH6, with the remaining 14% showing isolated loss of MSH6 [82].