Expression of a putative stem cell marker Musashi-1 in endometrium.

Aim: Firstly to examine the expression characteristics of Musashi (Msi)-1 in fetal endometrium, reproductive normal endometrium, endometrial hyperplasia and endometrioid adenocarcinoma, next, to focus on exploring the possibility that Msi-1 serves as a marker of the endometrial stem cells in-situ.

Methods: Immunohistochemical staining was performed to detect the expression of Msi-1 in 20 cases of fetal endometrium, 20 cases of normal endometrium, 20 cases of endometrial hyperplasia and 50 cases of endometrioid adenocarcinoma respectively.

Results: In fetal endometrium, Msi-1 positive cells were observed from the 12th week in epithelium, but the number of Msi-1 positive cells decreased with an increase in gestational age. In reproductive normal endometrium, Msi-1 expression presented as dispersed single cell and cell groups in the stroma adjacent to the myometrium. In endometrial hyperplasia and endometrioid adenocarcinoma, Msi-1 expression significantly increased and was more widely distributed.

Conclusions: Msi-1 positive cells mainly lie in the stroma of normal endometrium, and the distribution pattern is consistent with that of the speculated endometrial stem cells. The high expression of Msi-1 in fetal endometrium and endometrioid adenocarcinoma suggests that Msi-1 positive cells have several characteristics of stem cells, such as high proliferative potentiality and multipotency. Considering these factors, this makes Msi-1 potentially a promising stem cell marker.