The action of estrogens and progestogens in the young female breast

Publication date: Available online 28 March 2018Source: European Journal of Obstetrics & Gynecology and Reproductive BiologyAuthor(s): Irene Zolfaroli, Juan J. Tarín, Antonio CanoAbstractEvidence from different sources sustains a pro-oncogenic role of hormones, estrogens and progestogens, on the breast. The issue is of interest for young women, who are exposed to the hormonal changes imposed by the ovarian cycle and, often, take hormones with contraceptive purposes.Experimental and clinical studies show that both estrogens and progesterone are involved in mammary development during puberty and lactation, the changes being observed across mammalian species, including humans. Estrogen receptors, and more particularly the alpha isoform, participate in molecular processes of stem cells differentiation and epithelial proliferation through paracrine actions implicating growth factors. Progesterone also contributes through paracrine mechanisms involving one member of the tumor necrosis factor (TNF) family, the receptor activator of nuclear factor κB ligand (RANKL) and its receptor (RANK).Epidemiological studies have found that the length of the exposure to endogenous hormones, as determined by an early menarche or a late menopause, is a risk factor for breast cancer. Additional evidence has derived from studies with compounds modulating the estrogen or the progesterone receptors. Selective estrogen receptor modulators (SERM), like tamoxifen, have been shown to decrease the risk of...
Source: European Journal of Obstetrics and Gynecology and Reproductive Biology - Category: OBGYN Source Type: research