Biomarkers can be assessed for diagnostic, therapy-related or prognostic methods to identify phenotypes, such as a condition or disease, or the stage or progression of a disease, select candidate treatment regimens for diseases, conditions, disease stages, and stages of a condition, and to determine treatment efficacy. Circulating biomarkers from a bodily fluid can be used in profiling of physiological states or determining phenotypes. These include nucleic acids, protein, and circulating structures such as vesicles, and nucleic acid-protein complexes. The invention provides methods of assessing microvesicles in a biological sample. The invention also provides an aptamer to a microvesicle surface antigen. The aptamer may be used for therapeutic purposes.
