Second, our study used immunohistochemistry to detect the expression of mismatch repair proteins to determine the MSI status of rectal cancer; however, a study has shown that some colorectal cancers may lose MSH6 gene inactivation after receiving neoadjuvant therapy, and resulting in the loss of MSH6 protein expression, which would cause a certain degree of inaccurate in immunohistochemistry results (20). Here, MSH6 is linked to rectal cancer.