Gene variants that result in pathogenic (i.e., disease-causing) mutations in one of the four primary MMR genes, MSH2, MSH6, MLH1, and PMS2, result in an autosomal dominant hereditary cancer condition known as Lynch syndrome (LS), further underscoring the clinical relevance of intact MMR in the cell [275,276,277]. This evidence concerns the gene MRC1 and hereditary cancer.