The study of differential proteins in patients with peripheral lung cancer by surface-enhanced laser desorption/ionization time of flight mass technology

Abstract

To scan the protein mass spectra in the sera and bronchoalveolar lavage fluid (BALF) from patients with peripheral lung cancer, screen out the differential proteins, and explore the clinical significance of the differential proteins. SELDI-TOF-MS was used to detect the protein mass spectra and to screen out the differential proteins in the sera and BALF collected before and after lung biopsy in 20 patients with peripheral lung cancer and 20 patients with benign pulmonary diseases. The differential proteins were analyzed and the initial diagnostic models were set up. (1) There were 6 differential protein peaks in the sera of the 2 groups (P < 0.05). The protein with a mass/charge ratio (M/Z) of 6637 was selected to establish the diagnostic model. The sensitivity of diagnosing peripheral lung cancer was 70% (14/20), the specificity 90% (18/20), the accuracy 80% (32/40), the positive predictive value (PV+) 88% (14/16), the negative predictive value (PV-) 75% (18/24), and the area under the ROC curve (AUC) was 0.73. (2) There were 11 differential protein peaks in the BALF collected before lung cancer biopsy of the 2 groups (P < 0.05). The protein with a M/Z of 7982 was selected to establish the diagnostic model. The sensitivity of diagnosing peripheral lung cancer was 85% (17/20), the specificity 90% (18/20), the accuracy 88% (35/40), the PV+ 89% (17/19), the PV- 86% (18/21), and the AUC was 0.94. (3) There were 14 differential protein peaks in the BALF collected after lung cancer biopsy of the 2 groups (P < 0.05). The protein with a M/Z of 7671 was selected to establish the diagnostic model. The sensitivity of diagnosing peripheral lung cancer was 85% (17/20), the specificity 100% (20/20), the accuracy 93% (37/40), the PV+ 100% (17/17), the PV- 87% (20/23), and the AUC was 0.93. There were more differential proteins in BALF as compared with sera. There were more differential proteins in the BALF collected after lung biopsy as compared to that before lung biopsy. The AUC of the diagnostic models set up by proteins in BALF collected before and after lung biopsy were all above 0.9 and showed higher efficiency for the diagnosis of peripheral lung cancer as compared to proteins in sera. These differential proteins may be better tumor markers for the diagnosis of peripheral lung cancer at the early stage.