Because Delta-Notch signaling acts through a paracrine signaling mechanism, it is likely that in order to activate Notch in HCC36 Delta is expressed on neighboring cells in the tumor microenvironment that are not present in HCC cell lines (e.g., tumor vasculature)37 whereas the NOTCH ligand Jagged may be expressed in neighboring HCC cells. Here, DLL1 is linked to hepatocellular carcinoma.