While we have shown that radio-sensitization is MT1-MMP dependent, and invasion is a function of MMP2 downstream of MT1-MMP (Figure 3), we wanted to determine the possible contribution of MMP9, since MMP9 has been associated with poorer GBM patient outcome.28,44 Interestingly, while MMP9 inhibition (Supplementary Figure 16A) reduced invasion through a Matrigel/HA matrix (Supplementary Figure 16B), it did not affect radio-sensitization (Supplementary Figure 16C–I), indicating MT1-MMP directly promotes resistance to IR and that (R)-ND336 radio-sensitization is via MT1-MMP. Here, MMP9 is linked to glioblastoma.