Jagged-1 deletion caused deficits in vascular smooth muscle and fatal vascular defects, inhibiting sprouting angiogenesis, while Dll-4 blockade inhibits tumor growth, resulting in increased but dysfunctional angiogenesis, with other studies complementing an increased efficacy on the adjuvant chemotherapy when combined to anti-Dll-4 factors. This evidence concerns the gene JAG1 and neoplasm.