Another phase II randomized preoperative window-of-opportunity study in postmenopausal women with newly diagnosed, operable ER-positive breast cancer showed that adding pictilisib to anastrozole (an aromatase inhibitor) significantly enhanced suppression of breast cancer cell proliferation compared with anastrozole alone (Ki 67 staining; 83.8% vs. 66.0%) (Schmid et al., 2016). This evidence concerns the gene CYP19A1 and breast cancer.