The progesterone receptor (PGR) is a ligand-activated transcription factor with key roles in the regulation of female fertility. Much has been learned of the actions of PGR signaling through the use of pharmacologic inhibitors and genetic manipulation, using mouse mutagenesis. Characterization of rats with a null mutation at the Pgr locus has forced a reexamination of the role of progesterone i...

PURPOSE To describe the clinical features and outcomes of estrogen receptor negative (ER-) and progesterone receptor positive (PgR+) breast cancer. METHODS We retrospectively reviewed a well-characterized database of sequential patients diagnosed with early stage invasive breast carcinoma. Outcomes of interest were time to relapse (TTR) and overall survival (OS). Multivariable Cox proportiona...

We evaluated and compared Abbott Laboratories’ newly developed enzyme immunoassay(EIA) for measuring progesterone receptors (PgR) with that of DuPont’s steroidbindingassay (SBA). We also used both methodsto study the stability of PgR under various conditions. There were excellent correlations for all 59 cytosols compared (r = 0.94) and for the 44 cytosols containing PgR >10 fmol per milligram o...

The progesterone receptor (PGR) is a nuclear receptor transcription factor that is essential for female fertility, in part due to its control of oocyte release from the ovary, or ovulation. In all mammals studied to date, ovarian expression of PGR is restricted primarily to granulosa cells of follicles destined to ovulate. Granulosa cell expression of PGR is induced by the pituitary Luteinizing...

The aim of this study was to investigate the potential of progesterone receptor (PgR) as a biomarker for differentiating estrogen receptor (ER)-positive patients who fail to achieve a pathological complete response to neoadjuvant chemotherapy (NCT) with different prognoses. A total of 327 consecutive, locally advanced breast cancer patients with ER-positive disease were included in this study. ...

A review of assay results from more than 5500 patients revealed 283 patients in whom multiple breast cancer specimens were analyzed for progesterone receptor (PGR). All assays were performed in a single laboratory between 1975 and 1982 using the sucrose gradient technique. We considered only the 8S fraction of PGR. Simultaneous assays in 109 patients yielded 14% discordance [one assay with grea...

BACKGROUND The clinical significance of progesterone receptor (PgR) expression in estrogen receptor-negative (ER-) breast cancer is controversial. Herein, we systemically investigate the clinicopathologic features, molecular essence, and endocrine responsiveness of ER-/PgR+/HER2- phenotype. METHODS Four study cohorts were included. The first and second cohorts were from the Surveillance, Epid...

PURPOSE A lack of progesterone receptor (PgR) expression in oestrogen receptor-positive (ER+) tumours is associated with worse survival. PgR status is usually defined as positive or negative using 1% positive nuclei as a cut-off point. In this study, we aimed to assess the clinicopathologic characteristics of ER+/PgR-/HER2- tumours by comparing them with ER+/PgR+/HER2- tumours using a PgR cut-o...

BACKGROUND The immunohistochemical (IHC) evaluation of estrogen receptor (ER), progesterone receptor (PgR), Ki-67 and HER2 is considered a surrogate means for identifying the molecular subtypes of breast cancer with different prognosis. PATIENTS AND METHODS We explored patterns of recurrence in 4837 women with breast cancer defined as Luminal B (ER-positive and/or PgR-positive, HER2 positive ...

Progestins, progesterone derivatives, are the most critical signaling steroid for initiating final oocyte maturation (FOM) and ovulation, in order to advance fully-grown immature oocytes to become fertilizable eggs in basal vertebrates. It is well-established that progestin induces FOM at least partly through a membrane receptor and a non-genomic steroid signaling process, which precedes proges...