HGF and neoplasm: Indeed, joint overexpression of DRs and their ligand often promotes aggressive tumor progression, as was, for example, shown for HGF and c‐MET in NSCLC (Navab et al, 2009) or gastric cancer (Toiyama et al, 2012), suggestive of a positive selection for ligand‐induced rather than ligand‐independent signaling.