ESR1 and endometrial cancer: Estrogen dependency is one of the most important characteristics of low-grade endometrial endometrioid carcinoma [1], and further studies are needed to determine the difference between abnormal p53 low-grade endometrial cancer with retained diffuse ER expression, like the EClop53ab group in this study, and abnormal p53 low-grade endometrial cancer with decreased ER expression.