This study aimed at using matrix-assisted laser desorption ionization -time of flight mass spectrometer (matrix-assisted laser desorption ionization time-of-flight mass spectrometry, MALDI-TOF-MS) screening the difference serum peptides during epidermal growth factor tyrosine kinase inhibitors (EGFR-TKIs) treatment and exploring their significance of advanced NSCLC patients. This evidence concerns the gene EGFR and non-small cell lung carcinoma.