KITLG and gastrointestinal stromal tumor: KIT gene is located in chromosome 11p13 and contains 21 exons, which is a type 3 transmembrane receptor for mast cell growth factor, also known as stem cell factor, and the mutations in this gene are associated with gastrointestinal stromal tumors, mast cell disease, acute myelogenous leukemia, and piebaldism (7).