Figure 1.

S100P expression during embryonic implantation. During the implantation of the human embryo, S100P expression is closely correlated with the rhythmic hormonal changes in the endometrium, particularly with the levels of progesterone (P4). When a developing blastocyst is implanted, S100P is expressed in both the trophoblastic layer of the embryo, as well as in the endometrium of the uterine wall. When implantation is not achieved, S100P expression in the endometrium returns to a basal level. The graph below the image shows a correlation between progesterone and S100P, and is represented in red and blue, respectively.