Defining Secreted Glycan Alterations in Pancreatic Cancer

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DESCRIPTION (provided by applicant): The development of methods to accurately detect early pancreatic cancer and to better differentiate benign from malignant disease could greatly improve the outcomes for pancreatic cancer patients. It is known that malignant transformation of epithelial cells of the pancreas results in alterations in the carbohydrate chains of certain proteins secreted or released by these cells. Glycosylated proteins form the basis for current biomarkers for detecting pancreatic cancer and other adenocarcinomas, and refinement of these tests are predicted to enable detection of early pancreatic cancer. Our preliminary data has shown that a novel antibody-microarray technology allows the efficient detection of glycans on distinct proteins and the identification of specific glycan structures associated with pancreatic cancer. The method uses antibody microarrays to capture specific proteins from serum samples, followed by the incubation of a glycan-binding protein (such as a lectin) to quantify specific glycans on the captured proteins. Two classes of glycoproteins, mucins and carcinoembryonic-antigen-related proteins, are particularly associated with cancer, both in altered expression patterns and in altered glycan structures on the proteins. In the R21 phase, we will determine the levels of multiple specific glycans on members of those protein classes to test the hypothesis that the measurement of specific cancer-associated glycans on specific proteins, as opposed to measuring just protein or just glycan levels, will yield improved sensitivities and specificities for cancer detection. The R33 phase of the project will expand and thoroughly test the approach. The sensitivity and specificity of detecting pancreatic cancer using measurements of glycans on mucins, CEA proteins, and proteins identified in the R33 phase will be characterized in a large set of serum samples from subjects with pancreatic cancer, benign pancreatic disease, other cancers, and no disease. We expect to characterize the value of these measurements for disease diagnostics and to gain insights into the generality and frequency of specific glycan alterations on secreted proteins. Relevance to public health: The ability to more accurately diagnose cancers at earlier stages could lead to improved outcomes for many patients. This research could lead to significantly improved blood tests for the detection of cancer, as well as a powerful, generally- applicable platform for studying carbohydrate alterations on multiple proteins.