Why Gastrointestinal Stromal Tumors Develop

The way in which GIST grows, or the route the tumor takes when it spreads through the body, is called its pathophysiology.

Scientists are beginning to unravel some of the processes that go on inside cells that cause them to develop into GISTs. Normally these cells, like other cells in the body, grow and divide in a controlled fashion. But sometimes things can go wrong, allowing these cells to grow out of control and ultimately become cancerous.

Scientists have discovered that cells may grow in an uncontrolled manner as the result of an abnormality in their DNA. In GIST, a specific mutation causes a cellular enzyme known as KIT to be switched "on" all the time. KIT is an enzyme (called a "tyrosine kinase") responsible for sending growth and survival signals inside the cell. If it is ON, the cell stays alive and grows or proliferates. The overactive, uncontrolled mutant KIT enzyme triggers the runaway growth of GIST tumor cells. This insight into the way GISTs develop has already helped to identify new treatments for this sarcoma.

Risk factors for GIST

• Neurofibromatosis
  The most substantial risk factor for GIST is the presence of neurofibromatosis.
• Family History
  There are rare instances of familial GIST where several family members have the condition.