The values of the following diagnostic parameters were used for such an analysis: concentrations of tumor markers CEA and CA 19–9 (these are the oncomarkers used in conventional detection of CRC), CA 125, CA 15–3, HCG, and AFP; the level of AGA against glycans Tn, TF, SiaLeA, and Manβ1‐4ClcNAc (henceforth referred as “set of four glycans”) as well as LeC, LeY, and SiaTn; and the level of the immunoglobulins IgG, IgA, and IgM in serum. This evidence concerns the gene CEACAM5 and colorectal carcinoma.