HIGH-AFFINITY BINDING-SITES FOR GASTRIN-RELEASING PEPTIDE ON HUMAN COLORECTAL-CANCER TISSUE BUT NOT UNINVOLVED MUCOSA

Human colorectal cancer tissue and matched uninvolved mucosa from 21 p atients were examined by radioligand displacement for the presence of binding sites for bombesin-like peptides. Five cancers, but no univolv ed mucosa, expressed high-affinity, low-capacity bombesin binding site s (K-d = 6.53 nM, B-max = 58.6 fmol mg(-1) protein) of the gastrin-rel easing peptide (GRP)-preferring subtype (IC50 4.8 nM). Bombesin-like p eptides may have a role in the pathogenesis of colorectal cancer, and bombesin receptor antagonists may be of value in the treatment of rece ptor-positive tumours.