CEACAM5 and neoplasm: Generally, the lung cancer biomarkers are classified into two groups including DNA/genetic-based biomarkers (e.g., RAR-β mRNA, COX2, DAPK, RASSFIA, IL-8 mRNA, PRCS3, FHIT, K-ras mutant, p53 mutant) and protein-based biomarkers (e.g., CEA, CYFRA 21-1, TPA, tumor M2-pyruvate kinase, haptoglobin-R 2, APOA1, KLKB1, ProGRP) [16,28].