Mast/stem cell growth factor receptor (SCFR) is a protein in humans that is encoded by the KIT gene. Active mutations in this gene are associated with a small percentage of melanomas. C-KIT mutations also help the melanoma cells to grow and divide more quickly. The mutations are commonly found in melanomas that originate on the palms of the hands, the soles of the feet, or underneath the fingernails (called acral melanomas); inside the mouth or other mucosal (wet) areas; and on parts of the body chronically exposed to the sun.