Background
We have developed an exosome-based diagnostic platform that can identify highly specific biosignatures in exosomes derived from the blood of patients with colorectal cancer (CRC). While colonoscopy is the gold standard to screen and identify colon cancer it is estimated half of patients who are recommended for colonoscopy are not compliant. Often the lack of compliance is because many perceive a colonoscopy as an uncomfortable and invasive procedure. An ideal first step toward increasing participation in preventive strategies would be the development of a less invasive diagnostic test that could identify those patients that have a blood-based biosignature indicative of the need for biopsy by colonoscopy. Ideally this strategy would result in cancers being identified earlier and prevent disease-free individuals from undergoing an unnecessary invasive procedure. Current blood-based tests rely on increased levels of either carcinoembryonic antigen
(CEA) or carbohydrate antigenic determinant (CA 19-9). Unfortunately, CEA and CA 19-9 are neither organ-specific nor tumor-specific. In an attempt to provide a better blood-based biosignature for CRC we have developed a novel exosome-based diagnostic platform that is able to identify patients with CRC using an exosome-specific biosignature derived from plasma. Exosomes are endosome-derived vesicles between 40-
100 nm in diameter that are secreted by most cell types, including tumor cells. In this study, we demonstrate that a novel exosome-based assay can diagnose CRC from surface membrane protein biosignatures on exosomes derived from peripheral blood of patients with CRC.