In fact, PTEN-deficient endometrial tumor cells are shown to only be sensitive to the PARPi-PI3Ki combination therapy, but not to the PARPi monotherapy [37], while co-inhibition of both RAD51 and ATR is required to synergize ablation of PTEN-deficient melanoma and glioma cells [78], further underscoring the independence of RAD51/HR from the PTEN status. This evidence concerns the gene ATR and central nervous system cancer.