Since the evidence of activity of immune checkpoint inhibitors in patients with advanced mismatch repair (MMR)-deficient endometrial cancer (10) and considering that Lynch syndrome may account for about 3% of all endometrial cancers (11), it is recommended to screen all endometrial cancer patients with the use of immunohistochemical tests for MLH1, MSH2, MSH6, and PMS2 (12). This evidence concerns the gene MLH1 and endometrial cancer.