BRAF and melanoma: Additionally, Hata et al. have shown that mutations can arise while cells are exposed to a drug; as mentioned above, such mutations might appear to violate patterns of mutual exclusivity but the pattern only arose because of pathway down-modulation (Hata et al., 2016) Recently, Leung et al. have found a similar dependency on ERK activation limits in mutant BRAF-driven melanoma (Leung et al., 2018).