title: Progesterone and estrogen receptors in pregnant and premenopausal non-pregnant normal human breast.
abstract: We report here our studies of nuclear staining for the progesterone and estrogen receptors (PRA, PRB, ERalpha) and cell proliferation (MIB1) in the breast terminal duct lobular unit epithelium of 26 naturally cycling premenopausal women and 30 pregnant women (median 8.1 weeks gestation). Square root transformations of the PRA, PRB and ERalpha values, and a logarithmic transformation of the MIB1 values, were made to achieve more normal distributions of the values. PRA expression decreased from a mean of 17.8% of epithelial cells in cycling subjects to 6.2% in pregnant subjects (P = 0.013). MIB1 expression increased from 1.7% in cycling subjects to 16.0% in pregnant subjects (P < 0.001). PRB and ERalpha expression was slightly lower in pregnant subjects but the differences were not statistically significant. Sixteen of the non-pregnant subjects were nulliparous and ten were parous so that we had limited power to detect changes associated with parity. PRA was statistically significantly lower in parous women than in nulliparous women (32.2% in nulliparous women vs. 10.2%; P = 0.014). PRB (23.5 vs. 12.9%), ERalpha (14.4 vs. 8.6%) and MIB1 (2.2 vs. 1.2%) were also lower in parous women, but the differences were not statistically significant. The marked decreases in PRA in pregnancy and in parous women has also been found in the rat. A reduction in PRA expression may be a useful marker of the reduction in risk with pregnancy and may be of use in evaluating the effect of any chemoprevention regimen aimed at mimicking pregnancy. Short-term changes in PRA expression while the chemoprevention is being administered may be a more useful marker.
authors.affiliation: Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA.
authors.forename: DeShawn
authors.initials: D
authors.lastname: Taylor
authors.forename: Celeste Leigh
authors.initials: CL
authors.lastname: Pearce
authors.forename: Linda
authors.initials: L
authors.lastname: Hovanessian-Larsen
authors.forename: Susan
authors.initials: S
authors.lastname: Downey
authors.forename: Darcy V
authors.initials: DV
authors.lastname: Spicer
authors.forename: Sue
authors.initials: S
authors.lastname: Bartow
authors.forename: Malcolm C
authors.initials: MC
authors.lastname: Pike
authors.forename: Anna H
authors.initials: AH
authors.lastname: Wu
authors.forename: Debra
authors.initials: D
authors.lastname: Hawes
mesh_terms: D000028:Abortion, Induced; D000328:Adult; D001940:Breast / Q000737:chemistry* / Q000648:ultrastructure; D004847:Epithelial Cells / Q000737:chemistry; D047628:Estrogen Receptor alpha / Q000032:analysis*; D005260:Female; D005865:Gestational Age; D006801:Humans; D016462:Mammaplasty; D010298:Parity; D011247:Pregnancy / Q000378:metabolism*; D017697:Premenopause / Q000378:metabolism*; D011446:Prospective Studies; D011980:Receptors, Progesterone / Q000032:analysis*; D012189:Retrospective Studies; D044767:Ubiquitin-Protein Ligases / Q000032:analysis
chemical_list: C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D011980:Receptors, Progesterone; C101118:progesterone receptor A; C097314:progesterone receptor B; C513496:MIB1 ligase, human; D044767:Ubiquitin-Protein Ligases