To elucidate the role of the two close homologs APT-1 and APT-2, we selected a panel of NRAS mutant melanoma cell lines based on their previously characterized NRAS mutations in exons II and III and compared them to the BRAF mutant line SK-MEL-28, which also hyper-activates the MAPK pathway through BRAFV600E but not through mutant NRAS [12,13,28,29]. The gene discussed is BRAF; the disease is melanoma.