In the open-label, phase 2 PETREMAC trial (NCT02624973), pre- and postmenopausal patients with large T2 (>4 cm) or locally advanced ER/PGR>50 %, HER2-, and TP53 wild-type breast cancers received NET (tamoxifen + goserelin for premenopausal and letrozole for postmenopausal patients). Here, ESR1 is linked to breast carcinoma.