Studies comparing foregut carcinoids to specific biological markers have shown that foregut carcinoids, including bronchial, thymic, head and neck primary, have a higher sensitivity to CgA, similar to a specific tumor marker’s sensitivity in patients with pheochromocytomas and ileal carcinoid syndrome [140,143,151,152]. The gene discussed is CGA; the disease is hereditary pheochromocytoma-paraganglioma.