ESR1 and endometrial cancer: Given that the expressions and distributions of ER (ER-a and ER-b) and PR (PR-A and PR-B) have been associated with different survival of endometrial cancer in several studies [49,52], it is plausible to assume that different profiles of ER/PR expressions and distributions in histologic subtypes of endometrial cancer may contribute to the strong variation in survival by histologic subtypes.