ESR1 and breast cancer: For the treatment of breast cancer, some researchers have studied the estrogen receptor alpha-mitogen-activated protein kinases/Akt-cyclin D1/B-cell lymphoma-2 signaling pathway (Sui et al., 2014), regulation of myeloid cell leukemia-1, cyclin D1, and C-myc genes (Li et al., 2013), and more (Sun et al., 2015; Zu et al., 2015).