Curtin and Bastian in 2006 first described KIT mutations in melanoma. Although uncommon in non-acral cutaneous melanoma, these mutations are frequent in mucosal and acral melanomas. The KIT mutations in melanoma are similar to the KIT mutations in gastrointestinal intestinal stromal sarcomas (GIST) and these are believed to be driver mutations. In melanomas these mutations occur in an exclusive pattern in tumors without NRAS, BRAF, or GNAQ mutations. There is evidence that stage four melanoma patients with KIT mutations have a worse prognosis than other patients with similar stage and primary site.