Expression of estrogen and progesterone receptors in the human endocervix

Objective: To determine the messenger RNA and protein expression, as well as distribution of estrogen receptors (ER) and progesterone receptors (PR) in the endocervix compared with the endometrium. Setting: Volunteers in an academic research environment Materials and methods: Twelve volunteer patients undergoing total hysterectomy for benign indications. Patients did not receive any hormonal or GnRH analogues treatment prior to surgery. Hysterectomy samples were collected from volunteers. Tissues (endometrium and endocervix) were collected. Samples were transferred immediately to the research area and analyzed using Western blotting, reverse transcription-polymerase chain reaction (RT-PCR), and immunohistochemistry. Main Outcome Measures: Protein and mRNA expression of ER-α, ER-β, PR-A, and PR-B in endocervix compared with endometrium. Results: In both Western blot and RT-PCR, we detected ERα, PR-A, and PR-B mRNA and proteins in every sample. The ratio between PR-A and PR-B was about 2:1 in both the endometrium and endocervix regardless of menstrual cycle phase. In immunohistochemistry, these three receptors were detected in the lining and glandular epithelium, and to a lesser degree in the stromal layer. Estrogen receptorβ was minimally expressed in the glandular epithelium in immunohistochemistry sections with identical distribution of these receptors in the endocervix and endometrium. Conclusions: Further research is needed to elucidate the differential response of endocervix to steroid hormones.