We first identified the half-maximal inhibitory concentration (IC50) to the combination of the anti-EGFR moAb cetuximab and the selective MEK1/2 kinase inhibitor BAY-879766 (refametinib) used at a fixed ratio in order to achieve a synergistic effect as previously described [22] in a panel of 4 different KRAS-mutated human CRC cell lines: HCT116, HCT15, LOVO, SW480. This evidence concerns the gene MAP2K1 and colorectal carcinoma.