GSK1120212 resistance was associated with acquired mutations in MEK1 (MEK1V211D mutation in BRAF-mutant RKO and MEK1G128D/L215P mutations in KRAS-mutant HCT116; Fig. 3C)….SCH772984 is equally potent in naïve or GSK1120212-resistant, BRAF-mutant RKO colorectal cancer cells (RKOMR) or KRAS-mutant HCT116 colorectal cancer cells (HCT116MR).