ESR1 and breast carcinoma: In addition, prior investigators have reported a higher risk for breast cancer among women with higher levels of androgens independent of estrogen levels (Missmer et al., 2004; Peters et al., 2009) and although androgen receptor positivity is associated with better prognosis in ER+ breast cancers (Peters et al., 2009), it is also associated with acquired resistance to anti-estrogen (De Amicis et al., 2010; Rechoum et al., 2014).