To investigate the mechanism that underlies the ability of TEDs to enhance GBM cell death induced by TMZ and bleomycin, we examined the effects of TEDs to induce DNA damage as evidenced by immunostaining of GBM cells for γH2AX, which is the phosphorylated form of histone H2AX and functions as a sensitive marker for DNA double‐strand breaks.27 Here, H2AX is linked to glioblastoma.