IMR Press / CEOG / Volume 34 / Issue 4 / pii/2007058

Clinical and Experimental Obstetrics & Gynecology (CEOG) is published by IMR Press from Volume 47 Issue 1 (2020). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with S.O.G.

Editorial

Evidence that progesterone receptor antagonists may help in the treatment of a variety of cancers by locally suppressing natural killer cell activity

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1 Cooper Medical School of Rowan University, Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology & Infertility, Camden, NJ (USA)
Clin. Exp. Obstet. Gynecol. 2007, 34(4), 207–211;
Published: 10 December 2007
Abstract

Purpose: To propose a novel concept that progesterone receptor antagonists., e.g., mifepristone, may prove effective in treating avariety of cancers - even those not shown to be hormonally dependent or possessing progesterone receptors. Methods: Multiple human leukemia cell lines were evaluated for mRNA expression of an immunomodulatory protein called the progesterone-induced blocking factor (PIBF) that suppresses natural killer (NK) cell activity during normal pregnancy. Furthermore, we evaluated theeffects of progesterone (P) and mifepristone in PIBF protein expression. Finally, the effect of mifepristone treatment of mice with advanced leukemia was evaluated. Results: All tumor cell lines evaluated were found to express mRNA for PIBF and some were found to even express the PIBF protein. The adition of P to the media increased the expression of PIBF and mifepristone down-regulated its expression. Treatment of mice with spontaneous leukemia when they already had extensive disease seemed to increase the length and quality of their life. Conclusions: These data and other experience with mice with lung cancer and some anecdotal human cancer experience suggest that various cancers may utilize similar mechanisms used by the fetus to escape NK cell surveil-lance. Mifepristone and other progesterone receptor antagonists may deserve a clinical trial in human cancer even where there is no knowledge of the presence of progesterone receptors.

Keywords
Progesterone receptor antagonist
Cancer immunology
Natural killer cells
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