PARP inhibitors are widely used in clinical trials for several cancers carrying BRCA1/2 mutations or the signature of BRCAness such as ovarian cancer, prostate cancer, pancreatic cancer, glioblastoma, and soft-tissue sarcomas [32], and olaparib gained FDA approval for BRCA1/2-mutated ovarian cancer and castration-resistant prostate cancer [8, 9]. This evidence concerns the gene PARP1 and glioblastoma.