Figure 1: ESR1 gene and most common mutations (reprinted with permission from Ma et al. [3]). A schematic diagram of ESR1m and their frequencies in ER+ advanced breast cancer after endocrine therapy. The structural domains of ERα are shown, including the transcription activation function 1 (AF-1) domain, the DNA-binding domain (DBD), the receptor dimerization and nuclear localization (hinge) domain, and the ligand-binding domain (LBD) and AF-2 domain.