Causes of Gastrointestinal Stromal Tumors (GIST)
What causes GIST?
GISTs are caused by cells that grow and divide faster than they should. Most of the time, this excessive growth is caused by a defect in the protein called "KIT." GISTs tend to build up an excess amount of the KIT protein, which causes them to test "positive" for KIT. Ninety-five percent of GISTs are KIT-positive (KIT+).
Less is known about what causes the other 5% of GISTs—the ones that are not KIT+. These tumors are also caused by excessive cell growth, although it may be triggered by a different protein.
How does KIT cause GISTs to grow?
A KIT+ GIST usually starts when the KIT protein has a defect (mutation). KIT sends a signal that tells cells when to grow and divide. Usually, this signal is only “on” when more cells are needed. A KIT+ GIST occurs when the KIT protein is abnormal and does not turn “off.” When this happens, the abnormal KIT protein tells certain cells to grow and divide—even when they are not needed. Unlike in normal cells, this abnormal KIT protein never "turns off".
How a KIT mutation can lead to tumor growth
These abnormal cells keep growing and dividing, eventually becoming cancerous. The longer the cancerous cells live, the more likely it is they will become dangerous and spread to other parts of the body. That is why it is so important to control these cells by treating KIT+ GIST.
GIST Alliance
Patient Support Program
for GIST patients
& caregivers
Find out about
saving
on your prescription
co-pay
