Androgen Receptor Expression in Endometrial Carcinoma

Endometrial carcinoma (ECA) is frequently hormonally driven and can be treated with endocrine-based therapy, yet hormone receptor status is not routinely assessed. In particular, little is known about the significance of androgen receptor (AR) in ECA. Androgen has antiproliferative effects in the healthy endometrium and could serve a similar role to progesterone in curbing the progression of estrogen-dependent neoplasia. There may also be a subset of ECA that benefits from androgen antagonistic therapy. We herein investigate AR expression across ECA subtypes and compare its expression to estrogen receptor (ER) and progesterone receptor (PR). Immunohistochemical staining for AR, ER, and PR was performed on an endometrial tissue microarray containing 50 ECA with a variety of morphologic subtypes as well as 20 benign and 9 atypical hyperplastic endometria. AR was expressed by 54% (27/50) of ECA including 60% of low grade endometrioid carcinomas, 70% high grade endometrioid carcinomas, 70% serous carcinomas, 50% carcinosarcomas, and 20% clear cell carcinomas. High AR expression was chiefly restricted to a subset of serous carcinomas (50%). AR expression occurred most often in concert with ER staining, although 5 high grade cancers (1 serous carcinoma, 4 carcinosarcomas) showed AR expression in the absence of ER. In summary, AR positivity is seen in over half of ECA in our study, including the majority of low grade endometrioid carcinomas, high grade endometrioid carcinomas, and serous carcinomas. High level expression is seen in half of serous carcinomas and a subset of serous carcinomas and carcinosarcomas show some degree of AR staining in the absence of ER, suggesting a possible role for androgen inhibition in treatment of these cases.