In a prospective manner, they studied 293 patients with NSCLC in the IIIB‐IV clinical stage and found that CEA concentrations ≥40 ng/mL (RR 11.4; 95% CI, 1.7‐74; P < 0.01) were an independent risk factor.39 This result is consistent with the study by Ma. This evidence concerns the gene CEACAM5 and non-small cell lung carcinoma.