Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. These tumors are distinguished from leiomyosarcomas by the recognition that they contain both smooth and neural elements. In addition, these sarcomas are shown to express KIT and/or the platelet-derived growth factor receptor-α (PDGFRα). These tyrosine kinase receptors are commonly mutated, constitutively activating, and serve as the oncologic driver of these tumors. This biologic understanding has led to significant changes in the therapy of this disease, which has changed from a surgically treated disease to one that now incorporates therapy targeting the KIT and PDGFR tyrosine kinases.