Verification of GM2 Activator Protein for Potential Application as Lung Cancer Biomarker

Abstract

Lung cancer is the leading cause of cancer– related deaths worldwide. Finding effective biomarkers for early diagnosis would benefit available treatments. By 2-DE analysis, GM2 activator protein (GM2AP) was increased in urine samples of lung cancer patients. An increase of GM2AP level in urine samples of lung cancer patients were verified by Western blot analysis, using healthy donors as controls. Levels of urinary GM2AP in samples from the patients were significantly increased with 23-fold higher than that found in healthy controls. The increased level of GM2AP was also confirmed in serum samples of lung cancer patients. The levels of GM2AP were found with 14fold in lung cancer patients compared to those from healthy controls. Multiple reaction monitoring (MRM) assay revealed that the concentration of urinary GM2AP in lung cancer patients were at 1.960, 1.334 and 9.303 μM/mL, whereas in the healthy controls was found at 1.082, 1.177 and 1.028 μM/mL. The concentration of the serum samples of lung cancer patients and healthy controls were found at 2.113, 1.284 and 1.375 μM/mL, whereas in healthy controls were found at 0.995, 0.953 and 0.768 μM/mL, respectively. Therefore, we suggest that GM2AP might serve as preliminary candidate biomarker of lung cancer. Manuscript received June 9, 2014; revised September 3, 2014.