ESR1 and serous adenocarcinoma: Another immunohistochemical analysis of 180 endometrial carcinomas including 34 grade 3 endometrioid carcinomas and 15 serous carcinomas 8 found that IMP3, ER, PR, PTEN, p53, and p16 were detected in 20%, 82%, 68%, 61%, 39%, and 19% of grade 3 endometrioid carcinomas and 63%, 50%, 46%, 100%, 69%, and 90% of serous carcinomas, respectively.