In the cabozantinib trial, prespecified, exploratory analyses of potential plasma biomarkers of cabozantinib response were performed by plasma analysis of VEGF-A, hepatocyte growth factor (HGF), soluble VEGFR2 (sVEGFR2), and soluble MET (sMET) in OS and ES patients (16). Here, KDR is linked to Ewing sarcoma.