Instead, our data support a role for FGF-MEK1/2 signalling in regulating genes associated with Nodal signalling and stem cell characteristics in E12.5 XY germ cells, consistent with FGF and Nodal inducing pluripotency in XY germ cells and germ cell tumours, and the well-defined role for FGF in the derivation of pluripotent EGCs [9, 17, 41, 70–72]. Here, MAP2K1 is linked to germ cell tumor.