All primary cultures derived from either control eutopic endometrium and endometriosis lesions were positive for endometrial stroma cell markers CD10 and vimentin (Figure 3a) and negative for endothelial (PECAM1) and epithelial (EPCAM) markers (Figure 3b), indicating they represent the endometrial stromal cell compartment. The gene discussed is MME; the disease is endometriosis.