The use of targeting approaches to facilitate incorporation of TNF into tumour vasculature has also been investigated in preclinical models of PCa, whereby coupling TNF with the CNGRC peptide, a ligand for CD13 which is expressed on tumour vessels, enhanced the therapeutic index of doxorubicin against TRAMP C1 mouse prostate tumours in vivo [42]. Here, ANPEP is linked to neoplasm.