POMC and Cushing syndrome: We chose to utilize POMC as the intragranular secretory molecule to assess ESG formation in H1299 cells because small cell lung cancer, a representative malignant lung neuroendocrine cancer, often produces adrenocorticotropic hormone (ACTH), a mature form of POMC, as an ectopic hormone and is known to cause Cushing's syndrome (Perakakis et al. 2011).