HDAC9 and neoplasm: While HDAC inhibition reversed epithelial-mesenchymal transition via upregulation of E-cadherin, thereby suppressing the tumor’s metastatic potential in some studies, another study showed that inhibition of HDAC11 in breast cancer animal models led to increased migration and egress of tumor cells from lymph nodes to distant sites, via increase in RRM2 (Witta, 2012; Leslie et al., 2019).