For example, when the methylation of SHOX2 and RASSF1A is combined for lung cancer diagnosis, the sensitivity reaches 81.0%, and the specificity is 97.4%, significantly outperforming the serum biomarker carcinoembryonic antigen (CEA) with a sensitivity of 30.6% and a specificity of 100.0% [46]. The gene discussed is CEACAM5; the disease is lung cancer.