PRF1 and neoplasm: On the effector side, one of the newest HDACi, chidamide, led to enhanced lysis of K562 tumor cells in vitro by increased expression of proteins involved in NK cell functions like CD16, NKG2D, and granzyme A. Gene expression studies were performed and a time-dependent induction of NK cell receptors (CD16, NKG2D, and KLRG1), cytotoxic enzymes (granzyme and perforin), and molecules important for apoptosis (FASLG) was observed (Ning et al., 2012).