Cell line pools became resistant to high-dose PLX4032 (10 μmol/L) or GSK1120212 (1 μmol/L), as evidenced by robust proliferation in the presence of inhibitor (data not shown). Acquired activating mutations in KRASG13D or NRASG12C were identified in PLX4032-resistant BRAF-mutant A375 melanoma (Fig. 3A and B) or PLX4032-resistant BRAF-mutant RKO colorectal (Supplementary Fig. S6) lines, respectively.