e12561 Background: Exosomal RNA captures dynamic tumor biology and may overcome limitations of tissue biopsy and imaging, which, in the breast cancer segment, provide high false positivity and overdiagnosis (10-40%) and limitations with dense breast tissue with screening mammography and no reliable blood biomarkers for early recurrence or post-surgical risk stratification. A minimally invasive, real-time assay could improve detection and monitoring. Data suggest that gene expression signatures m