Background: Importin13 (IPO13) is a novel potential marker of corneal epithelial progenitor cells. We investigated the expression and localization of IPO13 in endometrial, endometriotic and endometrial carcinoma tissue.
Material/Methods: IPO13 expression in endometrial, endometriotic and endometrial carcinoma tissue was examined by immunohistochemistry, qPCR and Western blot.
Results: Immunohistochemistry studies showed that IPO13 protein was expressed mainly in cytoplasm of glandular epithelial cell and stromal cells. The rate of importin13-positive cells in proliferative phase endometrium was higher (by about 6-fold) than that in secretory endometrium (P<0.05) and the rate of importin13-positive cells in endometriosis and endometrial carcinoma was higher than that in normal secretory phase endometrial tissues (by about 4- and 9-fold, respectively). Immunofluorescence microscopy revealed co-localization of IPO13 with CD34, CD45, c-kit, telomerase, CD90 and CD146. QPCR revealed significantly increased IPO13 mRNA in endometriosis and endometrial carcinoma versus secretory phase endometrium (by about 2- and 10-fold, respectively). Western blot analysis showed that IPO13 protein is enhanced in endometriosis and endometrial carcinoma versus secretory phase endometrium (p<0.05).
Conclusions: These results demonstrate an increased expression of IPO13 in endometriosis and endometrial carcinoma, which could be involved in the pathogenesis of endometriosis and endometrial carcinoma; IPO13 can serve as an endometrial progenitor/stem cell marker.

Keywords: Karyopherins - metabolism, Gene Expression Regulation, Endometrium - pathology, Endometriosis - pathology, Endometrial Neoplasms - pathology, Blotting, Western, Antigens, CD - metabolism, Protein Transport, Proto-Oncogene Proteins c-kit - metabolism, RNA, Messenger - metabolism, Stem Cells - metabolism, Telomerase - metabolism, young adult