Updated project metadata. Increasing pre-clinical data suggest that chemotherapy may elicit pro-metastatic responses in breast cancer models. Primary tumours release extracellular vesicles (EVs) that can facilitate the seeding and growth of metastatic cancer cells in distant organs, but the effects of chemotherapy on pro-metastatic EVs are poorly understood. The goal of the project was to analyse the protein content in EVs released by the mouse breast cancer cell line 4T1 after treatment with the chemotherapeutic agent paclitaxel (PTX) or its vehicle control cremophor (CREMO).