We conducted a biomarker study to identify significant genes to predict efficacy of cetuximab (cet) based treatment using tumor samples from mCRC patients...LYZ and RNF43 genes were found to be significantly associated with OS (coefficients, 0.21; p = 0.013) and PFS (coefficients, -0.20; p = 0.037), respectively, in the FIRE-3 set. In the JACCRO set, high expression (log2>9.07) of CDX2 predicted a significantly longer PFS (p = 0.002).