Additionally, tumor markers like CEA (carcinoembryonic antigen), NSE (neuron-specific enolase), CYFRA 21-1 (a soluble fragment of cytokeratin 19 associated with epithelial cell tumors), and SCCA (squamous cell carcinoma antigen) do not allow for early detection of lung cancer [2]. Here, CEACAM5 is linked to lung carcinoma.