To test this hypothesis, we used a recombinant ephrinB2-Fc protein to activate EphB4 (schematically shown in Supplementary Fig. 16) on the control cells in the MEER tumor model (Fig. 4e) or in the ephrinB2 knock out cancer cells in the Moc2 tumor model (Fig. 4f). Here, EFNB2 is linked to cancer.