HDAC9 and neuroblastoma: Histone deacetylase (HDAC) inhibitors such as vorinostat (Suberoylanilide Hydroxamic Acid; SAHA) have been previously shown to promote Ku70 acetylation [59] and to inhibit cell growth and induce differentiation, apoptosis and cell cycle arrest in neuroblastoma cells and tumors [60–63].