What Causes Gastrointestinal Carcinoid Tumors?

Cancers can be caused by DNA mutations (changes) that turn on oncogenes or turn off tumor suppressor genes. This leads to cells growing out of control. Changes in many different genes are usually needed to cause carcinoid tumors. 

For more about how genes changes can lead to cancer, see Genes and Cancer.

Inherited gene mutations

Some DNA mutations can be passed on in families and are found in a person's cells. These are inherited (or familial) mutations. A small portion of carcinoid tumors are caused by inherited gene mutations.

Changes in 4 tumor suppressor genes are responsible for many inherited cases of carcinoid tumors.

• MEN1 (multiple neuroendocrine neoplasia 1). Changes in this gene account for most inherited cases. A smaller number are caused by inherited changes in the following genes:
• NF1 (Neurofibromatosis type 1) gene
• VHL (Von Hippel–Lindau) gene
• TSC1 or TSC2 (tuberous sclerosis complex 1 or 2) genes

Most carcinoid tumors are caused by sporadic changes (mutations) in oncogenes or tumor suppressor genes. Mutations are called sporadic if they occur after a person is born, rather than having been inherited.