Circulating cadherin-17 (CA17) in blood as a diagnostic biomarker for gastric cancer.

Abstract

10569 Background: The asymptomatic onset of gastric cancer (GC) frequently leads to delayed diagnosis resulting in poor survival. Conventional biomarkers (CA72-4, CEA) lack sensitivity, while emerging cfDNA methods remain costly and complex for routine screening. Our proprietary antigen, Cadherin-17 (CDH17), is selectively overexpressed in gastrointestinal (GI) malignancies. We developed a fully automated, high-throughput Chemiluminescence Immunoassay (CLIA) using proprietary antibodies to monitor the blood circulating levels of CA17 – the soluble form of Cadherin-17 protein in liquid biopsies. CA17 screening offers a complementary minimal invasive diagnostic method that identifies high-risk GC individuals for follow up endoscopy evaluations. Methods: A CLIA assay was designed to quantify circulating CA17 protein levels in human serum. The assay was established on the iShine i1910 automated platform, which integrates magnetic microparticle and acridinium ester labelling to generate luminescent signals. Four proprietary monoclonal anti-CA17 antibody clones were evaluated in various capture and detection pair combinations to identify the optimal antibody pairing for assay performance. Serum samples from 114 non-cancer individuals and 113 patients with histologically confirmed gastric cancer were analysed. Assay and biomarker performance was assessed by receiver operating characteristic (ROC) curve analysis to determine assay sensitivity and specificity. Results: Four capture/detection antibody pairings were evaluated. The clone 1–clone 2 combination demonstrated superior detection accuracy, yielding an AUC of 0.959 (90.3% sensitivity, 91.4% specificity). This optimal pairing revealed a highly significant difference in CA17 levels between the non-cancer and GC groups (Mann-Whitney test, ), confirming its ability to reliably distinguish high-risk individuals. In contrast, the clone 1–clone 3, clone 5–clone 1, and clone 1–clone 4 combinations exhibited inferior performance, with AUCs of 0.784, 0.705, and 0.680, respectively. Conclusions: The CA17 CLIA assay demonstrates high sensitivity and specificity for GC detection. As a minimally invasive blood-based test, it enables early identification of high-risk individuals for subsequent confirmatory endoscopy. This cost-effective blood test has the potential to allow screening of GC at the early stages and will significantly impact on patient survival.