A Hypothetical Model Suggesting Some Possible Ways That the Progesterone Receptor May Be Involved in Cancer Proliferation

The role of progesterone and the progesterone receptor in cancer: progress in the last 5 years

INTRODUCTION

Patients with various advanced cancers devoid of nuclear progesterone receptors (nPR) have demonstrated increased quality and length of life when treated with the PR modulator mifepristone, which likely works by interacting with membrane PRs (mPR).

AREAS COVERED

Two immunomodulatory proteins are discussed that seem to play a role in cancers that proliferate whether the malignant tumor is positive or negative for the nPR. These two proteins are the progesterone receptor membrane component-1 (PGRMC-1) and the progesterone-induced blocking factor (PIBF). Both PGRMC-1 and the parent form of PIBF foster increased tumor aggressiveness, whereas splice variants of the 90 kDa form of PIBF inhibit immune response against cancer cells.

EXPERT OPINION

The marked clinical improvement following 200-300 mg of mifepristone is likely related to blocking PIBF. In the low dosage used, mifepristone likely acts as an agonist for PGRMC-1 protein. Mifepristone may be less effective for cancers positive for the nPR because the nPR may be protective and blocking it may have detrimental effects. Based on this hypothetical model, the development of other potential treatment options to provide even greater efficacy for treating cancer are discussed.

Progesterone-induced blocking factor 1 and cytokine profile of follicular fluid of infertile women qualified to in vitro fertilization: The influence on fetus development and pregnancy outcome

Introduction: Progesterone is essential for both the initiation and the maintenance of pregnancy. The immunological effects of progesterone are mediated by the progesterone-induced blocking factor (PIBF), which is an immunomodulatory factor with anti-abortive properties. The aim of the research was to establish the cytokine profile and PIBF1 concentration in follicular fluid (FF) of patients undergoing in vitro fertilization (IVF).Methods: Seventy-eight patients who qualified for IVF underwent a detailed medical interview, including the course of fertility treatment and physical, gynecological, and cytological examinations. The concentration of PIBF1, IL-18, IL-2, IL-4, IL-6, IL-10, interferon-γ (IFN-γ), IL-1α, IL-1β, IL-5, IL-8, and IL-15 in FF during ovarian puncture was measured using commercially available ELISA kits.Results: IL-1 beta concentration was lower in the FF of patients with successful IVF. IL-8 concentration in FF correlated with the number of cumulus-oocyte complexes (COC-1), metaphase II (MII), and top-quality embryos. PIBF1 concentration had a positive correlation with the number of MII and top-quality embryos. IL-2 and IL-6 concentrations were positively correlated with the number of COC-1 and MII. An important parameter in assessing the chances of successful IVF is the number of top-quality embryos achieved.Conclusion: Higher PIBF1 concentration in FF may indicate a greater possibility of successful IVF due to the higher number of top-quality embryos. IL-1 beta concentration was found to be lower in the FF of patients with successful IVF. Therefore, PIBF1 and IL-1 beta in FF could be candidates for a marker of successful IVF.