MLH1 and Lynch syndrome: Moreover, genetic factors, such as familial adenomatous polyposis, Lynch syndrome, and several gene mutations, such as adenomatous polyposis coli (APC), mothers against decapentaplegic homolog 4 (SMAD4), Kirsten rat sarcoma viral oncogene homolog (KRAS), cellular tumor antigen p53 (TP53), DNA mismatch repair protein Mlh1 (MLH1), and DNA mismatch repair protein Mlh2 (MSH2) have been registered in most cases [1].