Bidirectional communications between genetics and epigenetics have been reported in cancers, with the detection of somatic mutations in genes encoding epigenome regulators (such as DNMT3A, IDH1, H3F3A) and inversely the identification of DNA hypomethylation or epigenetic silencing of DNA repair genes (such as MLH1 or BRCA1) that can cause genomic instability in cancer cells [24]. The gene discussed is MLH1; the disease is cancer.