CEACAM5 and lung cancer: Currently, traditional biomarkers for lung cancer identification, such as carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), and cytokeratin-19 fragment (CYFRA 21-1) are commonly utilized.38,39 However, the limited performance in the early-stage lung cancer with sensitivity around 0.6 hindered accurate detection, consequently raising the necessity of exploring novel biomarkers to offer new insights into the early diagnosis of lung cancer.40