PGR and breast cancer: In contrast to breast cancer, hormonal therapy in ER/PR positive EC is effective only in a minority of women, with response rates of approximately 22% to first-line hormonal therapy in advanced disease.68 Interpreting the current hormonal therapy literature in EC is challenging due to the unselected EC cohorts included in historic trials, different response criteria used in different studies, different hormonal treatment regimes and different cut offs used to define ER/ PR positive EC.