RPA1 and glioblastoma: Next, we assessed the RPA expression in acutely dissociated and Magnetic-Activated Cell Sorting (MACS) -sorted matched-paired GSCs (CD133 positive) and differentiated GBM cells (DGCs; CD133 negative) from the 4121, G01, G06 and G40 lines, and found RPA subunits RPA70 and RPA14 were preferentially expressed by GSCs (Figure 2B).