IGF1 and Hypoglycemia: The most common malignant causes of hypoglycemia include excessive insulin production (insulinomas), pancreatic beta-cell dysfunction (nesidioblastosis), and hypersecretion of catecholamines (pheochromocytoma) and insulin-like growth factor (IGF) (IGF-2 by sarcomas, gastrointestinal stromal tumors, solitary fibrous tumors, and IGF 3 by lung cancer).