The MLH1 Lys618Ala mutation (AAG>GCG; rs35502531), initially supposed to be a benign polymorphism, has been found to be significantly over-represented in sporadic cancers associated with Lynch syndrome; MLH1 Ala618 appears to have a reduced ability to bind PMS2, one of the MLH1 protein’s mismatch repair partners (Medeiros et al. 2012). This evidence concerns the gene MLH1 and Lynch syndrome.