الفهرس 
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Abstract
The expression of endometrial ERα and PR varies temporally and spatially across the menstrual cycle (Critchley HOD and Saunders PTK, 2009; Hayama M, et al., 2002; Fukunaka K, et al., 2001). We conducted this prospective analytic pilot study to examine if there is a spatial difference between anterior and posterior wall of the normal human endometrium at the molecular levels of ER and PR. To our knowledge no previous studies explored this issue.
Our cohort was consecutive 30 normal cycling women attending outpatient early cancer detection and hysteroscopic unit of Ain Shams University Hospital. Normality required rigorous evaluation of subjects’ medical and surgical history; physical, gynecological and hysteroscopic examination; and histological evaluation. The mean age was 31.8 years (range: 23-35 years) sampled in the proliferative phase of menstrual cycle (endometrium dating; range: day 6 - day 13; mean day 9). Histological evaluation by experienced pathologist assured normality of the endometrium and timing in the proliferative phase. We select this time of the cycle because expressions of ER-α and PR are known to be at their maximum (Pilka R, et al., 2006; Hayama M, et al., 2002; Mertens HJ, et al., 2001; Fukunaka K, et al., 2001; Noe M, et al.,1999)..
We used commercially available monoclonal antibodies that detect ERα but not ERß since ERß is known to be constitutively expressed with no regulation across the cycle (Talbi S, et al., 2006; Critchley HO, et al., 2002). Monoclonal anti-PR antibodies identified total PR(A and B) but do not specify specific PR isoform.
Our Immunohistochemical study revealed nuclear localization of ERα and PR in endometrial epithelial and stromal cells with staining for ERα being more intense than for PR in this phase of the cycle and ER-α staining is statistically more intense in the gland than in stroma. Our results are consistent with many reports that studied changes in immunoreactive staining of ER-α and PR in the functional layer across the normal cycle (Hayama M, et al., 2002; Fukunaka K, et al., 2001).
However, as regard the main study question, this pilot study revealed no statistically significant difference between the anterior and posterior endometrial walls in staining for ERα or PR as regard glandular cells, stroma cells or total immunopositive cells in functionalis layer. This lack of spatial or topographic differences of ER and PR is similar to what observed along the longitudinal axis of the uterus and in endocervix. No gradient could be observed in ER and PR expression in endometrium and myometrium when moving from the fundus towards the lower uterine segment (Noe M, et al., 1999) nor between the endocervix and endometrium (Al-Hendy A, et al., 2006). These and our results would alleviate investigators’ concerns about the topographical differences in ER and PR within the endometrium. In fact, the endometrium appears to function as one unit at the molecular levels of ER and PR.