To identify the target of the aptamer ex.50.T, we implemented a pull-down assay with a biotinylated ex.50.T and a scrambled (CtrlApt), unrelated sequence on protein extracts of EVs shed from patient-derived cell lines of a fibroadenoma (Pt.72) and two BCs: a HER2+ BC (Pt.37) and a TNBC (Pt.170). The gene discussed is ERBB2; the disease is Fibroadenoma.