Serum peptide profiles in patients with carcinoid tumors

Background: Patterns of elevated serum peptides may reveal additional markers and permit better classification of tumors based on (secondary) peptide secretion. Methods: Fasting peptide profiles were obtained from 31 carcinoid patients. vasoactive intestinal peptide (VIP), pancreatic polypeptide (PP), neurotensin, substance P, gastrin-releasing polypeptide (GRP), calcitonin, gastrin, and pancreastatin were measured. Peptide elevation patterns were correlated with disease sites, syndrome, and survival. Results: Elevations in patients were as follows: VIP 0%, PP 13%, neurotensin 10%, substance P 20%, GRP 3%, calcitonin 10%, and gastrin 3%. There were no consistent patterns of elevated peptides with regard to site or syndrome. Pancreastatin was elevated in 81% of profiles and was the only abnormal peptide in 57% of patients. Conclusion: Peptide profile results do not permit improved classification, predict syndrome development, or correlate with survival. In contrast, pancreastatin is elevated in most cases and may be utilized to monitor disease progression and evaluate response to therapy.