Screening the differential proteins in patients with lung squamous carcinoma or lung adenocarcinoma by SELDI-TOF-MS technology

Objective To research the differential proteins in serum,bronchoalveolar lavage fluid (BALF) and lung homogenate of patients with non-small cell lung cancer by SELDI-TOF-MS and analyze the clinical significance of differential proteins to identify lung squamous carcinoma or lung adenocarcinoma through an algorithm based on several distinct M/Z features.Methods SELDI-TOF-MS and WCX-2 chip were used to detect the protein mass spectra and screen out the differential proteins in the serum,BALF and lung homogenate of 20 patients with lung squamous carcinoma,20 patients with lung adenocarcinoma and 20 patients with benign pulmonary diseases.Then they were analyzed by Biomarker Pattern software and the initial diagnostic models were set up.Results ① Compared with benign pulmonary diseases group,differential protein peaks were two,nine and eight in the serum,BALF and lung homogenate of squamous carcinoma group( P ＜ 0.05).The proteins whose M/Z was 5124.24,7967.29and 10843.45,7914.59 and 8709.66 were selected to establish classification tree of diagnostic model.The sensitivity of diagnosing squamous carcinoma was 85 ％,80 ％,75％,the specificity was 65 ％,80 ％,90％,the accuracy was 75％,80％,83％,the positive predictive value was 71 ％,80％,88％,the negative predictive value was 81％,80 ％,78 ％ and the area under the ROC curve was 0.750,0.916,0.930.②Compared with benign pulmonary diseases group,differential protein peaks were eight,nine,seven protein peaks in the serum,BALF and lung homogenate of adenocarcinoma group ( P ＜ 0.05).The protein whose M/Z was 9295.79,7923.01,2452.49 were selected to establish classification tree of diagnostic model.The sensitivity of diagnosing adenocarcinoma was 75％,80％,70 ％,the specificity was 65％,90％,85 ％,the accuracy was 70 ％,85 ％,78 ％,the positive predictive value was 68 ％,89％,82％,the negative predictive value was 72％,82％,71％,and the area under the ROC curve was 0.844、0.933、0.825.Conclusions There are more differential proteins in BALF and lung homogenate in patients with squamous carcinoma or adenocarcinoma and they show higher efficiency to diagnose squamous carcinoma or adenocarcinoma compared with the proteins in serum.The sensitivity,specificity and accuracy of the diagnosis models set up by differential proteins in BALF (M/Z 7967.29 and 10843.45) and in lung homogenate (M/Z 7914.59 and 8709.66) of patients with squamous cacinoma and the protein (M/Z 7923.01) in BALF of patients with adenocarcinoma are about 75％ to 90％.These differential proteins are possible to be the biomarkers to diagnose lung squamous carcinoma and adenocarcinoma. Key words: SELDI-TOF-MS; Differential proteins; Lung cancer; Bronchoalveolar lavage fluid; Lung homogenate;  Serum