KRT19 and lung cancer: The biomarkers with diagnostic value for lung cancer mainly include cytokeratin 19 fragment (CYFRA 21-1) (Wang et al., 2020), neuron-specific enolase (NSE) (Wang K. Y. et al., 2025), and carcinoembryonic antigen (CEA) (Chen, 2025), etc. It is worth noting that non-small cell lung cancers accounts for the significant majority of lung cancer patients (Li et al., 2021), and CYFRA 21-1 DNA has been verified as a reliable diagnostic biomarker for NSCLC (Zhao et al., 2020).