Additionally, several P4-regulated genes, such as glycodelin, N-acetylglucosamine-6-O-sulfotransferase, and 17β hydroxysteroid dehydrogenase 2 (17βHSD2), have been found to be decreased in the eutopic endometrium of individuals with endometriosis (Burney et al., 2007). Here, PAEP is linked to endometriosis.