ESR1 and breast cancer: Building on this translational approach, the MASTER trial (MAmmary cancer STatins in ER positive breast cancer) is a large, double‐blind, randomised, placebo‐controlled phase III study in Denmark evaluating whether adding high‐dose atorvastatin (80 mg/day for 2 years) to standard (neo)adjuvant therapy improves invasive disease‐free survival (IDFS) and overall survival (OS) in women with early‐stage, estrogen receptor (ER)‐positive BC [27, 54].