,5,8 As NRP-1 is expressed by the endothelial cells in all tissues,3 peptides containing cryptic CendR owe their target selectivity to a combination of binding to primary receptor with a tumor-specific expression pattern, and to a proteolytic activation to expose the CendR sequence in the target organ.5, 6, 7, 8. This evidence concerns the gene NRP1 and neoplasm.