Exploring the human extraembryonic mesoderm using naive pluripotent stem cells

In this issue of Cell Stem Cell, Pham et al. report that naive human pluripotent stem cells can be differentiated into extraembryonic mesoderm cells (EXMCs). EXMCs are maintained for up to 70 days, resemble human and monkey extraembryonic mesoderm, and provide a model to study EXMC specification and function.