NET Cancer Day is celebrated annually on November 10th, worldwide! What is NET Cancer? What are neuroendocrine tumors? Neuroendocrine tumors (NETs) is the umbrella term for a group of unusual cancers which develop from cells in the diffuse endocrine system. NETs can affect people of any age, and can be slow-growing or very aggressive. They are found most commonly in the lung or gastrointestinal system, but they can also originate