title: Androgens and androgen receptors in breast cancer.
abstract: Aromatase (CYP19) converts adrenal and ovarian androgens into estrogens, which supports the growth of estrogen-dependent breast cancers. Anti-aromatase agents are displacing antiestrogens as the first-line treatment for estrogen receptor positive breast cancers. Androgens can act as estrogen precursors, but besides this capability they can also directly act on breast cancer cells by binding to androgen receptors, which are present in the majority of breast cancer specimens. Epidemiological and clinical evidences suggest that higher levels of circulating androgen increase the risk of developing breast cancer. Androgen receptor gene polymorphisms which render the more transcriptionally active receptors have been related to a lower risk of breast cancer. It is currently accepted that androgens act as antiproliferative agents in the presence of estrogens in some breast cancer cell lines. However, emerging evidence suggests that direct androgenic activity might also stimulate cell growth in a subset of estrogen-resistant breast tumors. Here we discuss the supporting evidence which proposes that androgens themselves are actively involved in breast carcinogenesis and its clinical behaviour.
authors.affiliation: Instituto Canario de Investigación del Cáncer, Canary Islands, Spain. bndiaz@icic.es
authors.forename: B
authors.initials: B
authors.lastname: Nicolás Díaz-Chico
authors.forename: F
authors.initials: F
authors.lastname: Germán Rodríguez
authors.forename: Ana
authors.initials: A
authors.lastname: González
authors.forename: Raquel
authors.initials: R
authors.lastname: Ramírez
authors.forename: Cristina
authors.initials: C
authors.lastname: Bilbao
authors.forename: A
authors.initials: A
authors.lastname: Cabrera de León
authors.forename: A
authors.initials: A
authors.lastname: Aguirre Jaime
authors.forename: Ricardo
authors.initials: R
authors.lastname: Chirino
authors.forename: Domingo
authors.initials: D
authors.lastname: Navarro
authors.forename: Juan C
authors.initials: JC
authors.lastname: Díaz-Chico
mesh_terms: D000728:Androgens / Q000502:physiology*; D001943:Breast Neoplasms / Q000503:physiopathology*; D018450:Disease Progression; D006801:Humans; D011110:Polymorphism, Genetic; D011944:Receptors, Androgen / Q000235:genetics / Q000502:physiology*; D018570:Risk Assessment
chemical_list: D000728:Androgens; D011944:Receptors, Androgen