HDAC9 and cancer: In another attempt to circumvent the limitations in cancer treatment, Cai et al. synthesized a series of multi-acting HDAC/EGFR/HER2 inhibitors, and their research culminated in the development of CUDC-101—a potent, hybrid derivative of quinazoline based anti-cancer drug, combining HDAC inhibitory pharmacophore into EGFR and human epidermal growth factor receptor 2 (HER2) (Table 15, Figure 18) [78].