DLL4 and chronic myelogenous leukemia, BCR-ABL1 positive: Considering that in murine models adhesion molecules, such as Notch1 and their ligands, are involved in the maintenance of CML stem and progenitor cells [16], the expression of Notch1, Jagged 2 and DLL4 were analyzed in both co-culture components, the MEG-01 cell line and endothelial cells.