ESR1 and serous adenocarcinoma: The combination of ER, PR, p16, p53, vimentin, PTEN, and IMP3 was 100% concordant with morphology in the largest study to address this differential diagnosis, with the combination of ER, p16, and p53 being interpreted as the most informative when applying a limited panel of 3 markers 3; however, the role of IMP3 in diagnosing serous carcinoma is more difficult to assess given the different cut-offs applied in different studies.