KIT mutations occur in approximately 15-20% of patients with mucosal melanomas. The majority ofKIT mutations occur within exon 11 and they are less frequent in other exons. The N822K mutation in exon 17 occurs within the kinase domain of KIT. Mutant KIT proteins have increased kinase activity and transforming activity in vitro. Although KIT activating mutations in exons 11 and 13 are typically sensitive to treatment with Imatinib, there was no response to treatment noted in patients harboring mutations in exon 17 (Ref. 4).

Regorafenib