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Gastrointestinal Stromal Tumors (GIST)

What Are Gastrointestinal Stromal Tumors?

Portrait of Dr. DeMatteo

GISTs are very rare tumors that start in special cells in the wall of the GI tract, called the interstitial cells of cajal. These cells, often called the "pacemaker cells," regulate your body processes, including digestion. They send signals to the muscles within your gastrointestinal tract to expand and contract, moving food and liquid through your digestive system.

GISTs are the most common type of sarcoma and can occur anywhere within the digestive tract. However, they are found most frequently in the stomach or small intestine. About 3,000 to 5,000 people are diagnosed with GISTs each year in the United States. 

Our cancer specialists have extensive experience in diagnosing and treating gastrointestinal stromal tumors. We work as a multidisciplinary team of medical oncologists, gastroenterologists, radiologists, pathologists and surgeons to develop the best treatment approach for you.

GIST Risks and Prevention

Our Gastrointestinal Cancer Risk Evaluation Program has specialists who are nationally recognized for their expertise in cancer and genetics. We provide information, care and support to help you throughout the entire risk evaluation process.

Penn's GI Cancer Risk team is familiar with and able to provide clinical, genetic and research services for people with concerns about the following conditions:

  • Hereditary and familial colon cancer: Diseases, including familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC) or Lynch syndrome, predispose people to develop colon polyps, which are benign growths and colon cancer. An early diagnosis combined with appropriate treatment and follow-up can dramatically lower the chances of developing colon cancer. A genetic counselor will also elevate MYH associated polyposis (MAP), Peutz-Jeghers syndrome and Juvenile Polypsis.
  • Hereditary and familial pancreatic cancer: This includes those with BRCA2, p16INK4a or SKT11 mutations, as well as those with family history.
  • Barrett's esophagus
  • Esophageal cancer
  • Stomach cancer: This includes those with the E-cadherin mutation.
  • Gastrointestinal sarcomas

GIST Second Opinions

We both give and welcome second opinions if you have been diagnosed with a gastrointestinal stromal tumor. We’ll meet with you to answer your questions, so you can make a more informed decision about your care.

During a second opinion, one of our GIST experts will review your medical history and your current diagnosis. We’ll then make a recommendation for the best treatment approach for you. If you’ve been diagnosed with a GIST and would like a second opinion from Penn Medicine, please request an appointment.

Ways to Give to the GIST Research Fund

To support the Abramson Cancer Center's GIST Research Fund, please contact Andrew Bellet at or 215-573-0548 or visit