ESR1 and breast cancer: Quantitative radiomic features extracted from breast MRI have been shown to be predictive of breast cancer tumour phenotypes.27 In this study, which was performed on 91 MRIs of biopsy-proven invasive breast cancers, imaging signatures were obtained to distinguish between estrogen receptor (ER) positive versus ER negative, progesterone receptor (PR) positive versus PR negative, human epidermal growth factor receptor 2 (HER2) positive versus HER2 negative and triple-negative versus other tumours, with AUC values of 0.89, 0.69, 0.65 and 0.67 respectively.