Human embryonic stem cell differentiation into endometrium-like cells. mRNA expression levels of CK18, EPCAM, ER, PR and PRL were analyzed in the differentiated cells on day 21 following induction by EB, mouse embryonic fibroblast feeder cells or co-culture with endometrial stromal cells. Data are presented as the mean ± standard deviation (n=3). *P<0.05, vs. respective EB group; #P<0.05, vs. respective feeder layer group. EPCAM, epithelial cell adhesion molecule; ER, estrogen receptor; PR, progesterone receptor; PRL, prolactin; EB, embryonic body; CK, cytokeratin.