CGA and carcinoid syndrome: In several NETs, such as pheochromocytomas [143,144], paragangliomas [140,145], carcinoid syndrome, the islet of Langerhans cell tumors of the pancreas [143,145,146], medullary thyroid cancer [147] and parathyroid and pituitary adenomas [148], plasma CgA levels may be high, although this is much less common (60%) in SCLC [140,149].