Nodal knockdown, pharmacologic inhibition of Nodal signaling, and Nodal blockade with polyclonal antibodies or with Embryonic Stem Cell (ESC) conditioned medium have been shown to suppress the invasive and tumorigenic phenotype of Nodal expressing, melanoma and breast cancer cells in vitro and in vivo [4, 8–10, 12–14]. Here, NODAL is linked to breast cancer.