Abstract: The state of protein phosphorylation and glycosylation can be key determinants of cellular physiology such as early stage cancer, but the development of phosphoproteins and/or glycoproteins in biofluids for disease diagnosis remains elusive. Here we demonstrate, for the first time, a strategy to isolate and identify phosphoproteins/glycoproteins in extracellular vesicles (EVs) from human plasma as potential markers to differentiate disease from healthy states. We identified close to 10,000 unique phosphopeptides in EVs by isolating from small volume of plasma samples. Using label-free quantitative phosphoproteomics, we identified 144 phosphoproteins in plasma EVs that are significantly higher in patients diagnosed with breast cancer than in healthy controls. Several novel biomarkers were validated in individual patients using Paralleled Reaction Monitoring for targeted quantitation. Similarly a group of glycoproteins in plasma EVs are identified.

Abstract: Noninvasive methods of determining breast cancer subtype in a subject are provided that employ newly identified biomarkers. Said methods comprise isolating a population of extracellular vehicles in a biofluid sample of a subject and detecting differential expression in one or more proteins or peptides therein. Such differential expression is compared to one or more expression profiles within a panel of biomarkers, with each expression profile in the panel associated with a subtype of breast cancer. Also provided are kits for detecting a subtype of breast cancer and/or identifying the recurrence thereof, each comprising an antibody, aptamer, or other detection means against the aforesaid biomarkers. Methods for monitoring treatment efficacy in a subject experiencing breast cancer using the same platforms are also provided.

Abstract: The state of protein phosphorylation and glycosylation can be key determinants of cellular physiology such as early stage cancer, but the development of phosphoproteins and/or glycoproteins in biofluids for disease diagnosis remains elusive. Here we demonstrate, for the first time, a strategy to isolate and identify phosphoproteins/glycoproteins in extracellular vehicles (EVs) from human plasma as potential markers to differentiate disease from healthy states. We identified close to 10,000 unique phosphopeptides in EVs by isolating from small volume of plasma samples. Using label-free quantitative phosphoproteomics, we identified 144 phosphoproteins in plasma EVs that are significantly higher in patients diagnosed with breast cancer than in healthy controls. Several novel biomarkers were validated in individual patients using Paralleled Reaction Monitoring for targeted quantitation. Similarly a group of glycoproteins in plasma EVs are identified.