In concordance with the crucial role of the arterial identity of definitive HE in vivo [59–62, 65, 67, 69, 71, 73] and the impact of arterialized HE through Notch signaling in vitro [64], overexpression of ETS1 or modulation of the MAPK/ERK signaling pathway induced HE with arterial characteristics and enhanced lineage potential [139]. This evidence concerns the gene ETS1 and hereditary elliptocytosis.