MLH1 and Lynch syndrome: Lynch syndrome is an autosomal dominant disorder caused by a germline mutation in one of several DNA mismatch repair (MMR) genes (mostly MSH2, MLH1, MSH6, and PMS2), and it is not only the most common cause of inherited colorectal cancer but it also accounts for approximately 3% of endometrial cancer (mainly endometrioid carcinoma often located in the lower uterine segment) (22–25).