MRC1 and cancer: Critically, approximately 40% patients with LS‐associated germline MMR mutations lacked the traditional indicators recommended for LS screening, such as age under 50, typical tumor histology, lower uterine segment involvement, and a positive cancer pedigree (as defined by the Bethesda criteria).27 Ring et al randomly screened 381 patients with newly diagnosed EC for MMR protein deficiencies, methylation, and mutation testing and identified 22 (5.8%) with LS.