As the relationship between serum CEA levels and BM, Arrieta et al. [21] demonstrated that serum CEA ≥ 40 ng/mL is a risk factor for developing BM (HR:1.5, 95%CI:1.09-2.2; p = 0.014), particularly in lung adenocarcinoma. The gene discussed is CEACAM5; the disease is lung adenocarcinoma.