HDAC9 and cancer: Notably, the combination of quinacrine or CBL0137 with HDAC inhibitors has demonstrated synergistic effects in multiple cancer types.[40, 56, 78] In our study, quinacrine also exhibited a therapeutic synergy with HDAC inhibitors in PTCL both in vitro and in vivo, suggesting that this combination epigenetic therapy may represent a favorable therapeutic strategy for PTCL.