A cytokine-peptide conjugate composed of the cytokine tumor necrosis factor alpha (TNF-alpha) chemically linked to the peptide CNGRC. The peptide moiety CNGRC, a ligand for the membrane-bound metalloprotease CD13, binds to endothelial cells of the angiogenic vasculature that express CD13 (also known as aminopeptidase N); subsequently, the TNF-alpha moiety induces apoptosis in endothelial cells expressing CD13, thereby inhibiting tumor-associated angiogenesis.