title: Recent data on intratumor estrogens in breast cancer.
abstract: The contribution of local synthesis versus circulatory delivery of normal breast as well as breast cancer tissue estrogens has remained a controversial area for decades. Novel data on tissue estrogen levels confirm a positive normal breast tissue to plasma concentration gradient for estrone, and to a smaller extent estradiol. Remarkably, this gradient is similar for pre- and post-menopausal women. Together with pharmacokinetic data on estrogen disposition, these findings suggest plasma and breast tissue estrogens to rapidly equilibrate, with circulating estrogens being a major contributor to breast tissue estrone levels. A likely explanation to the concentration gradient could be the fact that non-polar estrogens easily dissolve into tissue fat compartments as compared to plasma. While intratumor estrone levels are low as compared to benign tissue concentrations, intratumor estradiol is elevated in ER+ tumors. The correlation between intratumor estradiol levels and expression levels of dehydrogenases reducing estrone into estradiol but also intratumor ER concentrations are consistent with intratumor estrogen activation but also a scavenger effect of the ER.
authors: Section of Oncology, Institute of Medicine, University of Bergen, Norway. per.lonning@helse-bergen.no
authors: Per E
authors: PE
authors: Lønning
authors: Ben P
authors: BP
authors: Haynes
authors: Anne H
authors: AH
authors: Straume
authors: Anita
authors: A
authors: Dunbier
authors: Hildegunn
authors: H
authors: Helle
authors: Stian
authors: S
authors: Knappskog
authors: Mitch
authors: M
authors: Dowsett
mesh_terms: D001141:Aromatase / Q000235:genetics / Q000378:metabolism*; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000097:blood / Q000378:metabolism*; D004958:Estradiol / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D004967:Estrogens / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D004970:Estrone / Q000097:blood / Q000737:chemistry / Q000378:metabolism; D005260:Female; D006801:Humans; D009376:Neoplasms, Hormone-Dependent / Q000097:blood / Q000378:metabolism*; D017698:Postmenopause; D011960:Receptors, Estrogen / Q000378:metabolism
chemical_list: D004967:Estrogens; D011960:Receptors, Estrogen; D004970:Estrone; D004958:Estradiol; D001141:Aromatase