Patients with multiple primary cancers (PaMC and NPaMC) with variants in MLH1, MSH2, MSH6 and PMS2 showed a trend consistent with various LS-related cancers (Geary et al., 2008; Kastrinos et al., 2009; Weissman et al., 2012; Win et al., 2012; Møller et al., 2018; Gambichler et al., 2021), although whether they had LS was unknown (Supplementary Table 3, Supplemental digital content 4, http://links.lww.com/EJCP/A383). This evidence concerns the gene MLH1 and Leigh syndrome.