KRT19 and lung carcinoma: Several tumor markers for lung cancer have been identified and applied in the clinical diagnosis of lung cancer, such as neuron-specific enolase (NSE), glycoprotein antigen 153 (CA153), cytokeratin 19 fragment (CYFRA21-1) and glycoprotein antigen 125 (CA125) (Wang J. et al., 2018; Kang et al., 2019).