POMC and neoplasm: Melanin facilitates tumor cell immune evasion and disrupts host homeostasis by secreting factors such as CRH, urocortin, POMC derivatives (ACTH, MSH, endorphins), and biogenic amines (catecholamines, serotonin, melatonin), which regulate the HPA axis, sympathetic nervous system, cortisol levels, immune responses, and metabolism.