Clinically, clarifying MSI status contributes to the early detection of Lynch syndrome, which is an inherited cancer syndrome caused by a germline mutation in one of the several genes involved in the MMR pathway, including MLH1, MSH2, MSH6, and PMS2. Lynch syndrome is associated with an increased risk of various cancers, such as colorectal, endometrial, gastric, ovarian, small bowel, and hepatobiliary, as well as urothelial cancers, which may occur synchronously or metachronously [10]. Here, MLH1 is linked to cancer.