What is a neuroendocrine tumor?

A neuroendocrine tumor (NET) is an uncommon cancer type that forms in neuroendocrine cells (Neuroendocrine tumors may also be called islet cell tumors, carcinoid cancer, or carcinoid tumors). NETs can occur almost anywhere in the body, but neuroendocrine tumors most commonly form in the gastrointestinal tract, lung, and pancreas. Neuroendocrine tumors form in neuroendocrine cell.

Neuroendocrine cells can be found in many different organs. They carry messages from the nervous system to the endocrine system. In response to these messages, the endocrine system makes and releases hormones that control body functions like blood pressure, heart rate, digestion, breathing, and blood sugar. Neuroendocrine cells occur in these organs:

• Gastrointestinal tract (small intestine, rectum, stomach, colon, esophagus, appendix)
• Gallbladder
• Pancreas (islet cells)
• Thyroid
• Lungs
• Pituitary glands
• Thymus
• Kidneys
• Liver
• Prostate
• Skin
• Cervix
• Ovaries
• Testicles

What do NETs do?

Some NETs release hormones, which can cause a lot of disruptive symptoms. When a NET produces hormones, it is called “functional.” neuroendocrine tumor. When a NET does not produce hormones, it is called “nonfunctional.” 

Functional tumors produce “peptide” hormones. Peptide is a type of hormone that is made up of amino acids. Some of the peptide hormones NETs produce include:

• Somatostatin receptors
• Vasoactive intestinal peptide (VIP)
• 5-hydroxytryptamine serotonin (5-HT)
• Gastrin

The excess peptide hormones released by a tumor can cause signs and symptoms.

What are the signs and symptoms of neuroendocrine tumors?

Signs and symptoms of neuroendocrine tumor vary depending on where the tumor is located. Learn about neuroendocrine tumor sites:

• Pancreas
• Lung
• Gastrointestinal tract
• Adrenal glands

What causes neuroendocrine tumors?

Sometimes, something goes wrong inside the neuroendocrine cell and it stops behaving as it should. The neuroendocrine cell grows and divides faster than it should. The excess cells form tumors. We don’t yet know at what point in the neuroendocrine cell lifecycle it becomes cancer. But NETRF has funded millions of dollars in scientific research to answer this question. See what we are learning.