Adenomyotic Glands Are Highly Related To Endometrial Glands

Research question: How closely related are adenomyotic and endometrial glands?Design: In this study, the mRNA and protein database www.proteinatlas.org was searched for proteins expressed predominantly in the endometrial glands. Specificity was tested with tissue microarrays. Biopsy specimens of endometrial, adenomyotic tissue, or both, were collected after surgery from 21 women without endometriosis, 20 women with endometriosis, 18 women with adenomyosis together with endometriosis and 12 women with adenomyosis alone. Tissue expression was analysed by immunohistochemistry.Results: Two proteins were identified: calcyphosine (CAPS), and msh homeobox 1 (MSX1). A high abundance and good specificity in endometrial glands were found. Both proteins, CAPS and MSX1, showed a high specificity for endometrium and are both localized in the luminal cells and epithelial cells of the glandular and adenomyotic glands. No significant differences were found between CAPS- and MSX1-positive endometrial glands between cases with and without endometriosis. Also, no cycle-specific different expression was found. Furthermore, a close relationship between the adenomyotic glands and the endometrial glands for CAPS (range 63.0-98.3%) and for MSX1 (range 87.1-99.3%) could be demonstrated. Only 11.2% and 6.8% negative glands for CAPS and MSX1 were identified in all tissues from all patients, respectively; none were negative for both proteins.Conclusions: Taken together, our results show that the protein expression pattern of adenomyosis is nearly identical to those of the endometrium with and without endometriosis, thus suggesting endometrial glands as the main source for adenomyotic glands.