MRC1 and cancer: To better understand the influence of mutated MMR gene (MLH1 and MSH2), founder variant (MLH1:c.1528C>T), and sex on cancer risk in LSVH, we calculated the cumulative risk of any cancer (i.e., both colonic and extracolonic cancers combined), colonic, and extracolonic cancers separately using Kaplan–Meier analysis across three distinct groups.