(1)A measure of 150 pmol/L—the upper limit of normal CART levels.(2)NET patients—mean plasma CART 440 pmol/L; elevated in 56% of patients.(3)CART levels with chromogranin A measurement—improved sensitivity for neuroendocrine malignancy from 85% to 91%; the sensitivity of CgA and CgB—89%.(4)Increased CART levels—pancreatic tumor (71% of all patients, 95% of patients with progressive disease), midgut tumor (45%), tumor of unknown origin (63%).(5)Mean CART levels in plasma were higher in progressive diseases than in stable tumors of all types. This evidence concerns the gene CHGB and neoplasm.