DUSP4 and melanoma: In addition, not only BRAF‐mutant but some NRAS‐mutant melanoma cell lines were sensitive to inhibition of DUSP4 and PPP2R2A. PPP2R2A was confirmed to be a fitness gene in the two cell lines included in the initial CRISPR‐Cas9 screens, IGR1 and WM983B as well as in the independent A375 cell line.