INS and neuroendocrine neoplasm: Both the North American (NANETS) and European (ENETS) Neuroendocrine Tumor Societies recommend measurement of chromogranin A in both non-functioning and functioning tumors, as well as evaluation of specific hormones, such as insulin, C-peptide, pro-insulin, gastrin, glucagon, vasoactive intestinal peptide, parathyroid hormone-related protein, adrenocorticotropic hormone, and somatostatin based on clinical manifestations [5].