Altered gene expression profiling in endometrium: evidence for progesterone resistance.

Progesterone plays an important role in regulating multiple events in the uterus. It controls endometrial proliferation and differentiation, which are important for uterine function. Dysregulation of progesterone signaling leads to impaired physiological functions. Indeed, aberrant expression of progesterone-regulated genes in the endometrium has been implicated in several gynecologic disorders, including endometriosis, polycystic ovarian syndrome (PCOS), and endometrial hyperplasia. Although several investigators have analyzed eutopic endometrial expression of progesterone-target genes, the genesis and consequences of progesterone resistance remain unclear. We review evidence for progesterone resistance in endometrium of women with endometriosis, PCOS, and endometrial hyperplasia, and we identify possible mechanisms associated with reduced progesterone activity in endometrium of (some) women with these gynecologic disorders that have a significant impact on women's health and well-being.