ESR1 and cancer: They bind weakly to the estrogen receptor alpha (ERα) of the reproductive organs such as the uterus, ovaries, and breast, but bind more strongly to the estrogen receptor beta (ERβ) found in the brain, arteries and bone [7], and have been associated with beneficial effects in humans, such as the relief of hot flushes, and the prevention of osteoporosis, cardiovascular diseases, and cancers [8].