However, due to the broad range of pan-HDACi targets within cells, more targeted HDACi are being tested pre-clinically such as the HDAC6 specific molecules like ACY-738 or tubastatin A. ACY-1215/Ricolinostat was one of the first HDAC6 specific inhibitors to enter clinical trials for myeloma, lymphoma and metastatic breast cancer (Vogl et al., 2017; Silva et al., 2020; Amengual et al., 2021). Here, HDAC6 is linked to plasma cell myeloma.