Upregulation of the Endometrial Stem Cell Marker Numb in the Endometrium of Adenomyosis Patients Suggests a Potential Role in Pathogenesis

Introduction: Adenomyosis, a prevalent gynecologic condition involving invasion of endometrial tissue into the myometrium, remains poorly understood in terms of its molecular pathogenesis. Numb, an important regulator of cellular destiny and stem cell maintenance, has been implicated in numerous proliferative diseases; however, no role for Numb in adenomyosis has been explored to date. This research examines the degree to which Numb protein may play a role in adenomyosis pathogenesis by regulating the regulation of endometrial and myometrial cells. Design: This study analyzed Numb protein expression in tissues from 21 adenomyosis patients and 14 controls using im-munohistochemistry. Numb levels were evaluated in eutopic endometrium, ectopic le-sions, and myometrium. Results: Compared to controls (p < 0.001), adenomyosis patients' eutopic endometrium and myometrium showed considerably higher levels of numb expression. It was predominantly observed in single cells rather than clusters. No sig-nificant variation was noted across menstrual cycle phases. Elevated Numb levels in the myometrium suggest a potential role in tissue invasion. Conclusion: This study presents new evidence of elevated Numb expression in adenomyosis, suggesting that it may play a part in the pathophysiology of the disease and that it is a useful marker for dysregulation of endometrial stem cells.