title: Progesterone and Overlooked Endocrine Pathways in Breast Cancer Pathogenesis.
abstract: Worldwide, breast cancer incidence has been increasing for decades. Exposure to reproductive hormones, as occurs with recurrent menstrual cycles, affects breast cancer risk, and can promote disease progression. Exogenous hormones and endocrine disruptors have also been implicated in increasing breast cancer incidence. Numerous in vitro studies with hormone-receptor-positive cell lines have provided insights into the complexities of hormone receptor signaling at the molecular level; in vivo additional layers of complexity add on to this. The combined use of mouse genetics and tissue recombination techniques has made it possible to disentangle hormone action in vivo and revealed that estrogens, progesterone, and prolactin orchestrate distinct developmental stages of mammary gland development. The 2 ovarian steroids that fluctuate during menstrual cycles act on a subset of mammary epithelial cells, the hormone-receptor-positive sensor cells, which translate and amplify the incoming systemic signals into local, paracrine stimuli. Progesterone has emerged as a major regulator of cell proliferation and stem cell activation in the adult mammary gland. Two progesterone receptor targets, receptor activator of NfκB ligand and Wnt4, serve as downstream paracrine mediators of progesterone receptor-induced cell proliferation and stem cell activation, respectively. Some of the findings in the mouse have been validated in human ex vivo models and by next-generation whole-transcriptome sequencing on healthy donors staged for their menstrual cycles. The implications of these insights into the basic control mechanisms of mammary gland development for breast carcinogenesis and the possible role of endocrine disruptors, in particular bisphenol A in this context, will be discussed below.
authors.affiliation: Swiss Institute for Experimental Cancer Research (C.B., R.J.) and Brain and Mind Institute (K.H.), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Cathrin
authors.initials: C
authors.lastname: Brisken
authors.affiliation: Swiss Institute for Experimental Cancer Research (C.B., R.J.) and Brain and Mind Institute (K.H.), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Hess
authors.affiliation: Swiss Institute for Experimental Cancer Research (C.B., R.J.) and Brain and Mind Institute (K.H.), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Rachel
authors.initials: R
authors.lastname: Jeitziner
mesh_terms: D000818:Animals; D001559:Benzhydryl Compounds / Q000009:adverse effects; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000378:metabolism* / Q000503:physiopathology*; D049109:Cell Proliferation; D004195:Disease Models, Animal; D052244:Endocrine Disruptors / Q000009:adverse effects; D004703:Endocrine System / Q000502:physiology*; D005260:Female; D006728:Hormones / Q000502:physiology; D006801:Humans; D008321:Mammary Glands, Animal / Q000378:metabolism; D008597:Menstrual Cycle; D051379:Mice; D008810:Mice, Inbred C57BL; D010636:Phenols / Q000009:adverse effects; D011374:Progesterone / Q000502:physiology*; D051381:Rats; D012307:Risk Factors; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D052244:Endocrine Disruptors; D006728:Hormones; D010636:Phenols; D011374:Progesterone; C006780:bisphenol A; D000098826:Bisphenol A Compounds