In this project, 4T1 parental cells (4T1/WT) were exposed to increasing concentrations of epirubicin (EPB) to establish a novel multi-drug resistant CSC-like breast cancer cell line (4T1/EPB). The ubiquitinated proteins were enriched from 4T1/WT or 4T1/EPB derived cell lysate using a-Al2O3-Vx3 nanoparticles to produce the covalently linked product UPs nanovaccine. Label-free LC-MS/MS mass spectrometry was used to detect the type and amount of enriched proteins of UPs from the 4T1/WT cells and the 4T1/EPB cells.