In contrast to the correlation between high CYP2C9 expression and TMZ response, a significant correlation of ABCB1 high expression was noted in patients not responding to TMZ (median expression value = 147) in comparison to the responder GBM patients (median expression value = 112) (Fig. 5F; p = 0.0492). This evidence concerns the gene CYP2C9 and glioblastoma.