ESR1 and endometriosis: However, CCC commonly arises from endometriosis (4.5% of extragonadal ERHs) and typically show estrogen receptors (ERs) downregulation with lack the immunohistochemical ER expression; moreover, mesonephric-like adenocarcinomas, a rare new entity which also downregulate ER and PR, can also exceptionally arise from endometriosis [69,73,74,75,76,77,78,79,80,81,82,83,84].