COL18A1 and acute myeloid leukemia: Investigation of the cytokine release profile of HUVECs showed that these cells release very low or undetectable levels of IL1β, GM-CSF, and HGF under in vitro culture conditions; however, they release (i) several mediators important for angioregulation including MMP-2, endostatin, and various angioregulatory chemokines [32]; and (ii) cytokines known to promote AML cell proliferation including CXCL8 and PDGF [32, 33].