Proteins in the EVs of MCF-10A and MDA-MB-231 cells were determined by mass spectrometry at Beijing Proteome Research Center using a LC-MS/MS platform comprising a nanoflow high-performance liquid chromatograph (HPLC) instrument (EASY-nLC 1000 nanoflow LC, Thermo Scientific, USA) coupled with a LTQ Orbitrap Velos mass spectrometer (Thermo Scientific, USA).