Unexpectedly, molecular analyses of nevi (moles), benign lesions which very rarely give rise to invasive melanomas, showed that they also had a high rate of Braf and Nras mutations.9 This finding suggested that oncogenic mutations in the RAS-RAF-MEK-ERK pathway are very early events in the development and pathogenesis of cutaneous melanomas. The gene discussed is MAP2K7; the disease is cutaneous melanoma.