HDAC9 and neoplasm: For example, although HDAC activity generally seems to impair anti-tumor immunity, the intrinsic HDAC activity of Tcf1 and Lef1 is crucial for maintaining CD8+ T cell identity.512,513 Protein arginine methyltransferase 5 (PRMT5), another promising immune-epigenetic target with its inhibitors undergoing clinical evaluation and producing clinical benefits,514 has been reported to help improve anti-tumor immunity in melanoma515 (Table 3).