KIT and gastrointestinal stromal tumor: Further, although approximately 70% of c-Kit mutations in melanoma and GIST occur in exon 11, there is a preponderance of the activating L576P, exon 11 variant in melanoma (~34% of c-Kit mutations) and this mutation shows poor imatinib sensitivity in GIST [10], and variable sensitivity in melanoma [5, 7].