Profiling of autoantibodies in sera of pancreatic cancer patients.

BACKGROUND: Although autoantibodies to cancer antigens are candidates for biomarkers, no comprehensive studies to detect cancer-specific antibodies have been performed. This study identified autoantibodies in the sera of pancreatic cancer (PC) patients using proteomics based on a wheat germ cell-free protein production system. METHODS: We constructed a biotinylated protein library of 2,183 genes. Interactions between biotinylated proteins and serum antibodies were detected by AlphaScreen® assay. Relative luminescence signals of each protein in 37 PC patients and 20 healthy controls were measured, and their sensitivity and specificity for PC were calculated. RESULTS: Luminescence signals of nine proteins were significantly higher than those of healthy controls, with calcium and integrin binding 1 (CIB1) protein showing the greatest significance (p = 0.002). Sensitivity, specificity, positive predictive value and negative predictive value of CIB1 autoantibody alone for PC were 76, 70, 82, and 61 %, respectively, and 97, 35, 74, and 88 %, respectively, when the four most significant proteins were combined. Presence of these autoantibodies did not vary significantly with other clinicopathological characteristics. CONCLUSION: Several autoantibodies, including CIB1, are potential biomarkers for PC.