MLH3 and cancer: Its functions include: i) participation in the repair of DNA replication errors and maintenance of microsatellite stability; ii) participation in meiosis 1 crossover regulation and maintenance of germ cell stability; and iii) participation in alkylation damage and reduction of mutation accumulation induced by environmental carcinogens.The presence of malignant pathogenic mutations in MLH3, e.g., by interfering with the normal functioning of the MLH1-MLH3 complex, induces dominant-negative effects that lead to MSI and cancer susceptibility.