Distribution and clinical role of KIT gene mutations in melanoma according to subtype. A study on 492 Spanish patients

BACKGROUND: KIT mutations are primarily associated with acral and mucosal melanoma, and have been reported to show higher prevalence in chronic sun-damaged (CSD) than non-CSD melanomas. OBJECTIVES: To investigate the prevalence of KIT mutations in melanoma according to subtype, and to determine the clinical role of such mutations. MATERIAL AND METHODS: Here we present results from a study on a Spanish population of 492 melanomas, classified according to the latest World Health Organization (WHO) guidelines. We analyzed the mutational status of KIT and correlated with different clinical variables related to sun exposure and family history. RESULTS: KIT mutations were significantly more frequent in acral (3/36; 8.3%) and mucosal (4/8; 50%) melanomas than in non-acral cutaneous melanomas. No significant difference was observed in KIT mutational status between CSD and non-CSD melanomas. CONCLUSION: Our results suggested that KIT mutations in melanoma tumors are unrelated to nevus proneness or chronic sun damage, but their presence is associated with aggressive melanomas showing ulceration, vascular invasiveness, and increased Breslow thickness. These findings were consistent with those reported by The Cancer Genome Atlas network.