MRC1 and neoplasm: In a study by Roth et al, of patients with synchronous or metachronus malignancies, 69% of patients showed concordant MMR results, whereas 31% showed discordant results.53 Thus, even if the first tumor has common variants of the wide‐type allele of the MMR genes, it is not uncommon for subsequent tumors to develop MMR mutations in the context of LS.