19 Background: Esophageal adenocarcinoma (EAC) continues an upward trend. Mortality rate and treatment costs for EAC are very high overall and significantly increase with disease stage. Diagnosis at early stage (T1) compared to advanced stage (T3) improves 5 year survival from 20% to 80-90%. Endoscopic surveillance has been ineffective in reducing EAC. Therefore the need for better diagnostic tools for early detection.Previously we reported validation of a list of serum glycoprotein biomarker candidates for EAC in an Australian cohort (Shah et al. 2015 Mol Cell Proteomics. 14:3023-39.). Here we further evaluate the serum and tissue expression of top candidate C9 in an independent cohort from the USA. Methods: Serum samples (n=38) and FFPE tissue sections (n=34) were collected from participants with IRB approved protocol, from the Ochsner Clinic undergoing endoscopic surveillance for Barrett’s and esophageal cancer. Serum glycoprotein candidates were measured using lectin magnetic bead array-coupled multiple reaction monitoring assay (Shah et al. 2015 Mol Cell Proteomics. 14:3023-39.). Immunohistochemistry was optimised for complement component C9 antibody. Initial evaluation of 2 different antibodies gave similar results, thereafter, a polyclonal antibody from Sigma Aldrich was used. Staining was assessed by a gastrointestinal pathologist. Results: Specific glycosylated forms of 3 candidate serum biomarkers were confirmed to be significantly different between EAC and benign groups (p<0.05, Kruskal-Wallis). The diagnostic value for the 3 individual markers, complement component C9, gelsolin and alpha-1-antichymotrypsin (Serpin A3) was 0.71 to 0.82 area under the receiver operating curve (AUROC). A multivariate panel consisting of 8 glycoprotein biomarkers achieved AUROC of 0.96, indicative of high diagnostic value. Immunohistochemistry of tissues detected high levels of C9 in BE and EAC compared to normal squamous epithelium. Infiltrated lymphocytes showed variable staining. Conclusions: We propose a novel candidate biomarker complement component C9 which could add to current endoscopic surveillance strategy for early detection of adenocarcinoma.
Treatment of Early-Stage Esophageal Adenocarcinoma
