Moreover, the combination of vorinostat with external radiotherapy has recently entered clinical trials with non–small cell lung cancer (NCT00821951) and glioblastoma (NCT03426891) patients to assess safety, tolerability, and efficacy, thus suggesting that HDAC inhibitor treatment is a clinically feasible radiosensitizing strategy for TAT in cancer patients. This evidence concerns the gene HDAC9 and glioblastoma.