NRAS and melanoma: Of relevance to our study, CCLE data indicate that high DUSP4 expression is predictive of increased sensitivity to selumetinib, with an odds ratio of 2.3.53 Similarly, in a panel of pan-negative (wild-type BRAF, NRAS, KIT, GNAQ and GNA11) melanoma cell lines, cells expressing higher levels of DUSP4 have been reported to show significantly greater sensitivity to MEK inhibition.51 This correlates with our finding that CHL-1 cells that express lower DUSP4 were less sensitive to selumetinib than the higher-expressing SK-MEL-23 cell line (Fig. 4e).