CHEK2 and glioblastoma: Addressing whether the coordinated expressions of Ape1 and Chk2 is associated with TMZ response of glioblastoma cells, we analyzed two patient-derived early-passage glioblastoma cells IN-GB-2 and IN-GB-10 that are characterized by differential levels of Ape1 and Chk2 expressions, both at the protein and mRNA level (Fig. 6A; Fig. S8E,G).