Somatic Activation of KIT in Distinct Subtypes of Melanoma

Oncogenic mutations in KIT were found in three of seven tumors with amplifications. Examination of all 102 primary melanomas found mutations and/or copy number increases of KIT in 39% of mucosal, 36% of acral, and 28% of melanomas on chronically sun-damaged skin, but not in any (0%) melanomas on skin without chronic sun damage. Seventy-nine percent of tumors with mutations and 53% of tumors with multiple copies of KIT demonstrated increased KIT protein levels.

KIT is an important oncogene in melanoma. Because the majority of the KIT mutations we found in melanoma also occur in imatinib-responsive cancers of other types, imatinib may offer an immediate therapeutic benefit for a significant proportion of the global melanoma burden.