Comparison of the Utility of Cocaine- and Amphetamine-Regulated Transcript (CART), Chromogranin A, and Chromogranin B in Neuroendocrine Tumor Diagnosis and Assessment of Disease Progression

Context: Prognosis in patients with neuroendocrine tumors (NETs) is often poor, frequently reflecting delayed diagnosis. Hence, accurate and practical NET markers are needed. Cocaine- and amphetamine-regulated transcript (CART) peptide is a potential novel NET marker. Design and Participants: Circulating levels of CART peptide and the established NET markers chromogranin A (CgA) and chromogranin B (CgB) were measured using RIA in 353 patients with NET (normal renal function) and in controls. Clinical data were collected retrospectively. Main Outcome Measure(s): The comparative and combined utility of CART, CgA, and CgB for diagnosis and assessment of disease progression was measured in different NET subtypes. Results: CgA and CgB in combination improved diagnostic accuracy in patients with gut NETs, nongastroenteropancreatic NETs, and NETs with an unknown primary origin compared with each biomarker alone. Measuring CART did not further improve diagnosis in these NET subtypes. For pancreatic NETs, CgB was ...