Haptoglobin is a serological biomarker for adenocarcinoma lung cancer by using the ProteomeLab PF2D combined with mass spectrometry.

Identification of serological biomarker is urgently needed for cancer screening, monitoring cancer progression, treatment response, and surveillance for recurrence in lung cancer. Therefore, we try to find new serological biomarker that has more specificity and sensitivity for lung cancer diagnostics. In this study, the 2-D liquid phase fractionation system (PF2D) and mass spectrometry approach has been used for comparison the serum profiles between lung cancer patients and healthy individuals. Eight proteins were identified form PF2D and subsequently by mass spectrometry. Among these proteins, haptoglobin (HP) and apolipoprotein AI (APOA1) were chosen and validated with turbidimetric assay. We found that HP levels were significantly higher and APOA1 levels were significantly lower in lung cancer patients. However, after the participants were stratified by gender, the expression trends of HP and APOA1 in lung cancer patients existed only in men, which is gender specific phenomenon. HP, APOA1 and carcinoembryonic antigen (CEA), used for distinguishing lung adenocarcinoma, had a sensitivity of 64%, 64% and 79%, respectively. Area under the ROC curve (AUC) of HP, APOA1 and CEA were 0.768, 0.761 and 0.884, respectively. When restricted to male subjects, HP, APOA1 and CEA showed sensitivity of 89%, 73% and 100%, respectively. AUC of HP, APOA1 and CEA were 0.929, 0.840 and 0.877, respectively. Therefore, our results showed that combined with PF2D system and mass spectrometry, this is a promising novel approach to identify new serological biomarkers for lung cancer research. In addition, HP may be a potential serological biomarker for lung adenocarcinoma diagnostics, especially in male subjects.