Breast cancer is the most common cancer, and the leading cause of cancer-related deaths, among females world-wide. Recent research suggests that extracellular vesicles (EVs) play a major role in the development of breast cancer metastasis. | Ekström et al. BMC Cancer 2022 22 50 https s12885-021-08870-w RESEARCH Open Access Characterization of surface markers on extracellular vesicles isolated from lymphatic exudate from patients with breast cancer Karin Ekström1 2 Rossella Crescitelli1 2 Hafsteinn Ingi Pétursson1 2 Junko Johansson1 2 Cecilia Lässer3 and Roger Olofsson Bagge1 2 Abstract Background Breast cancer is the most common cancer and the leading cause of cancer-related deaths among females world-wide. Recent research suggests that extracellular vesicles EVs play a major role in the development of breast cancer metastasis. Axillary lymph node dissection ALND is a procedure in patients with known lymph node metastases and after surgery large amounts of serous fluid are produced from the axilla. The overall aim was to isolate and characterize EVs from axillary serous fluid and more specifically to determine if potential breast cancer biomarkers could be identified. Methods Lymphatic drain fluid was collected from 7 patients with breast cancer the day after ALND. EVs were isolated using size exclusion chromatography quantified and detected by nanoparticle tracking analysis electron microscopy nano flow cytometry and western blot. The expression of 37 EV surface proteins was evaluated by flow cytometry using the MACSPlex Exosome kit. Results Lymphatic drainage exudate retrieved after surgery from all 7 patients contained EVs. The isolated EVs were positive for the typical EV markers CD9 CD63 CD81 and Flotillin-1 while albumin was absent indicating low contamination from blood proteins. In total 24 different EV surface proteins were detected. Eleven of those proteins were detected in all patients including the common EV markers CD9 CD63 and CD81 cancer-related markers CD24 CD29 CD44 and CD146 platelet markers CD41b CD42a and CD62p as well as HLA-DR DP DQ. Furthermore CD29 and CD146 were enriched in Her2 patients compared to patients with Her2- tumors. Correspondence .
