In the subgroup analysis of patients with adenocarcinoma histologycal type, frequency ± standard error of CNS metastasis development at 12 months of diagnosis were 16.4 ± 0.03% (95% CI, 16.34 – 16.46%) and 67 ± 0.09% (95% CI, 66.91 – 67.09), in patients with CEA serum levels < 40 ng/mL, and ≥ 40 ng/mL, respectively. The gene discussed is CEACAM5; the disease is adenocarcinoma.