HDAC9 and cancer: The anti-cancer effect of HDAC inhibitors was also identified in canine urothelial carcinoma cells (cUC), OS, prostate cancer (PCa) and hemangiosarcoma (HSA) (Elshafae et al. 2017; Murahari et al. 2017; Eto et al. 2019; Suzuki et al. 2022).