HDAC9 and cancer: The HDAC inhibitor Vorinostat (SAHA), although so far only FDA approved for cancer treatment in adults but not yet in children, is in several clinical trials for pediatric patients for example in combination with bortezomib (Phase 1, NCT01132911) or lenalidomide (Phase 1, NCT03050450) for the treatment of high grade or progressive central nervous system tumors, and with etoposide (Phase 2, NCT01294670) for relapsed and treatment refractory sarcomas.