One of the findings in a recent large investigation analysing the outcomes of patients with mCRC with BRAF mutations was that the most marked divergence between the BRAF-mutant and wild-type cancers occurred following progression on or after benefit from first-line chemotherapy.9 Our results with serum CA 19-9, CEA, IL-6 and CRP strongly suggest that the prognostic prediction provided by these biomarkers also largely concerns advanced stages of mCRC. This evidence concerns the gene IL6 and cancer.