Liquid biopsy assessment with a comprehensive 324 genes Foundation One Liquid NGS assay (Foundation/Roche) will provide not only an integrated analysis of RAS and BRAF genes mutational status along all the duration of the trial, but also an extensive study of potential biomarkers of response to cetuximab based treatment that, together with the analysis of the influence of gut microbiome on anti-tumor activity will allow to a better tailored anti-cancer treatment in mCRC. This evidence concerns the gene BRAF and neoplasm.