Objective:To compare and analyze the difference in serum proteins between patients with early-stage lung squamous carcinoma(LSC)and normal subjects and identify the proteins related with LSC.Methods:Serum samples were collected from 6 normal subjects and 6 patients with stage 1 of LSC.2-DE were performed to separate serum proteins.After silver staining

the proteins of differential expression were analyzed and then identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF-MS).Resluts:There were an average of(939±40)spots and(962±27)spots on 2-DE matching of two groups and the matching rates were 89.2 % and 87.1%.From the two groups

25 differential protein spots with over three times of differential expressions were analyzed by MALDI-TOF-MS.8 proteins were identified

of whith 3 proteins were expressed only in sera of the patients with early-stage LSC.Up-regulated expression was observed in 1 protein and down regulated expression or scarce expresseion were observed in 4 proteins in the patient serum group.Conclusion:Compared with the normal subject group

the sera in the early-stage lung squamous carcinoma patients group showed differential expression in protein profile.The proteins with differential expression are expected to be the serum markers for lung squamous carcinoma.