Abstract: OBJECTIVE: To identify the specific tumor markers of lung cancer induced by irradiation for diagnose and therapy by proteomics．METHODS：Samples of BEP2D cells irradiated with 0，1.5 and 3.0 Gy γ-rays for 24 h were cultivated and collected，and total protein was separated with the two-dimensional gel electrophoresis. The peptide mass fingerprints were obtained using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS)for differentially expressed proteins. RESULTS：10 peptide mass fingerprinting were revealed in the mass spectra identification，8 of them approved in the database (2 null)，and 1 duplicated．There were 7 points identified in the initial tests by Mascot software in the NCBInr databates，such as cyclophilin A，myosin light chain 2，cytokeratin 9，α-enolase，triosephosphate isomerase 1，makorin ring finger protein 1，c-myc promoter-binding protein 1. CONCLUSION：The 7 proteins probably were the special proteins related to lung cancer induced by irradiation，which might be used for further study of the functions of the proteins．

Key words: proteome, BEP2D cell, γ- rays, cyclophilin A, myosin light chain 2