To further test our hypothesis that TMZ-resistant disease has an increase of EWSR1 cytoplasmic aggregates and CLK2 expression, we performed immunohistochemistry (IHC) on an independent set of four matched patient samples from pre-TMZ treatment to post–TMZ-resistant recurrent GBM (table S2, cohort 2). This evidence concerns the gene EWSR1 and glioblastoma.