A previous study using a 42-plex human cytokine array to analyze the serum of NSG mice engrafted with Nalm6-GFP leukemia cells reported high levels of PDX-intrinsic PDGF-AA and FLT-3 L as well as lower levels of FGF-2, VEGF-A, and TNFα (47). Here, TNF is linked to leukemia.