MLH1 and infection: Furthermore, the infection has been reported to downregulate MMR components, including MutL Homolog 1 (MLH1), MutS Homolog 2 (MSH2), MSH3, MSH6, Post-Meiotic Segregation Increased 1 (PMS1), PMS2, and DNA Polymerase Delta Subunit 3 (POLD3) [35,49,50,51].