Our findings point toward a previously unrecognized role for CXCR2 and its ligands in directing EC activation and neovascularization in asthma specifically, because lower levels (2- to 3-fold) of these ligands present in CM of non-asthmatic controls did not significantly induce sprout outgrowth from EC spheroids. The gene discussed is CXCR2; the disease is asthma.