GRP and lung cancer: However, the positive outcome may generate new issues related to the rate of overdiagnosis of indolent cancer.[5] Furthermore, people screened for lung cancer with LDCT comprise a small proportion.[6] Currently, some serum tumor markers, such as carcinoembryonic antigen, squamous cell carcinoma-associated antigen, cytokeratin-19 fragment, neuron-specific enolase, and pro-gastrin-releasing peptide, can significantly improve the diagnosis of lung cancer, but specific markers are still lacking.[7–9]