The decline of Mcl-1 levels upon irradiation have been correlated before with apoptosis induction in Jurkat T-lymphoma cells.9 In addition, Mcl-1 increased resistance of glioblastoma cells to apoptosis induced by temozolomide or the death ligand TRAIL.17, 18 Thus, the failure to downregulate Mcl-1 levels in A172, Ln229, and LKI cells could be responsible for survival after irradiation. Here, MCL1 is linked to glioblastoma.