For example, CEA (carcino embryionic antigen) is a 180-kDa glycoprotein as well as a carcinoembryonic antigen of fetal embryonic development, in addition to this, it is also a biomarker as its concentration level is increased in blood of patients with all lung cancer types (Figure 5) [48,79]. This evidence concerns the gene CEACAM5 and lung carcinoma.