**3.3.2 Androgen Receptor (AR)**

Androgen receptor gene is present in the endometrial tissue and the pelvic organs, which are the targets for endometriotic implants. The AR was detected in endometriosis, adenomyosis and endometrial carcinoma (Horie K et al 1992). Endometrial cysts are monoclonal in origin and are related to the reaction with AR. The endometrioma might be formed from an independent monoclonal ovarian endometrial cell after inactivation of AR allele in the X chromosome (Fujimoto J et al, 1999). The proliferation and differentiation of the endometrium are mediated mainly by the Estrogen and Progesterone receptors. However, Androgen receptor also plays a role in modulating the cyclic change of the endometrium.

*Androgen Receptor (AR) gene* trinucleotide polymorphism has been associated with endometriosis (Yao-Yuan-Hsieh et al, 2001). The AR gene has a polymorphic cytosine, adenine and guanine (CAG) microsatellite in exon 1 that codes for variable length glutamine repeats in the amino-terminal domain of the AR protein (Hsieh.Y Y et al, 2004). The 21-CAG repeats may be associated with some determinants for endometriosis formation as indicated in a study by Lattuada et al, (2004) in Italian women.

### **3.3.3 Progesterone Receptor (PR)**

Estrogen and progesterone receptors are present in the ectopic endometrium but in lower concentrations than in eutopic endometrium. Cyclical variation in the receptor population has not been observed and also there seems to be a difference in the way that estrogen is handled by the endometrium at the two sites (Vierikko P et al, 1985).

The expression of the variants of the Progesterone Receptor (PR-A and PR-B) was shown to be aberrant in endometriotic tissues, which may indicate a role of the progesterone receptor in the pathogenesis of endometriosis (Nisolle M et al, 1994; Attia GR et al 2000).

The progesterone receptor gene is located in chromosome region 11q22-23.PROGINS polymorphism has been studied in association with breast cancer (Wang-Gohrke S et al, 2000) and ovarian cancer (Vigano P et al, 2006). The data indicate that a mutated progesterone receptor gene contributes to the development of disease in hormone-sensitive tissues

*Progesterone Receptor (PR) gene PROGINS* polymorphism has been shown to be associated with endometriosis in Caucasian women (Weiser F et al, 2002). The secretory phase of the menstrual cycle is controlled largely by progesterone, and this sex steroid hormone is absolutely required for normal implantation and pregnancy. PROGINS polymorphism of the progesterone receptor may be associated with an increased risk of endometriosis in Italian women (Lattuada et al, 2004).
