of Gastrointestinal stromal tumors (GIST)
Gastrointestinal stromal tumors (GIST) are a relatively rare but aggressive type of soft-tissue sarcoma. These cancers are most commonly found in the stomach or small intestine where they originate in the cells of Cajal, which are specialized cells lining the digestive tract responsible for initiating the rhythmic movement that propels food and solid waste through the GI tract. It is estimated that there are between 3,300 and 6,000 individuals diagnosed with GIST every year in the United States, most often in older adults.
GISTs are characterized by specific genetic abnormalities that cause overactivity of a specific gene, called the c-kit proto oncogene that results in the overproduction of certain tyrosine kinase proteins. Tyrosine kinases are responsible for helping the cancer cells survive and grow and their discovery led to the development of one of the first precision cancer medicines designed to target a specific genetic cancer causing abnormality. Tyrosine kinase inhibitors (TKI) are precision cancer medicines that blocks tyrosine kinase activity slowing the growth of the cancer. TKI’s are currently the main medical treatment for GIST.
Prior to the development of the first TKI-Gleevec patients with advanced GISTs faced a life expectancy of 18 months, now many of the initial Gleevec treated patients remain alive over 10 years from initiation of therapy. As a result of current DNA sequencing techniques, doctors increasingly also understand which class of patients benefit the most from Gleevec and other TKI’s.
Next: Symptoms & Signs of GIST
Nowain A, Bhakta H, Pais S, et al.: Gastrointestinal stromal tumors: clinical profile, pathogenesis, treatment strategies and prognosis. J Gastroenterol Hepatol 20 (6): 818-24, 2005.
Demetri GD, von Mehren M, Blanke CD, et al. Efficacy and safety of imatinib mesylate in advanced gastrointestinal stromal tumors. New England Journal of Medicine. 2002;347:472-480.
Demetri GD, van Oosterom AT, Blackstein M, et al: Phase III, multicenter, randomized, double-blind, placebo-controlled trial of SU11248 in patients following failure of imatinib for metastatic GIST. Journal of Clinical Oncology. 2005;23:308s, Abstract #4000.