A gastrointestinal stromal tumor (GIST) is a relatively rare mesenchymal tumor of the gastrointestinal (GI) tract and is defined as a spindle cell or epithelioid neoplasm expressing a c-kit (CD117) immunophenotype, which is the tyrosine kinase (TK) component [1]. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.