DLL4 and cancer: SOS/VOD is associated with exposure to pyrrolizidine alkaloid-containing herbal remedies [5], chemotherapy prior to hematopoietic stem cell transplantation [2] and oxaliplatin-based adjuvant or neo-adjuvant chemotherapy for CRLM [6, 7], DLL4 (an endothelium-specific NOTCH ligand) represents an attractive target in cancer therapy due to its role in tumor angiogenesis and its contribution to the maintenance and proliferation of cancer stem cells [8] with several anti-DLL4 antibodies having been developed and tested both in pre-clinical and clinical settings [9–11].