MLH1 and endometrial carcinoma: In contrast, there were no co-occurring mutations of TP53, which is frequently mutated in endometrial serous and serous-like carcinomas, or of POLE, which is altered in ultramutated endometrial carcinomas, or of MSH2, MSH6 and MLH1, which are mutated in microsatellite unstable endometrial carcinomas (S2 Fig).