We treated NRAS-mutant (YUGASP, SKMEL-2, SKMEL-103, and M318), BRAF-mutant (SKMEL-28 and A375), NF1-mutant/null (MeWo and YUTOGS), and NRAS/BRAF/NF1 wild-type (YUVON) melanoma cells with three DNA replication stress-inducing agents: aphidicolin, camptothecin, and hydroxyurea (Durkin et al., 2008; O'Connell et al., 2010; Petermann et al., 2010). The gene discussed is NRAS; the disease is melanoma.