CHEK2 and cancer: To investigate the functional implications of the Ape1/Chk2 cross-talk for human cancer etiology, we performed a search using The Cancer Genome Atlas (TCGA)27, 28, which revealed that the patients with glioblastoma who express higher levels of APEX1 have a better survival rate (R2: Microarray Analysis and Visualization Platform; Kaplan-Meier Scanner) (Fig. S3E).