HDAC6 and plasma cell myeloma: Because HDAC6 is as a tubulin-deacetylase crucially involved in the aggresome pathway which functions as an alternative protein degradation mechanism in the cell through autophagic clearance of misfolded proteins [43], its presence has been suggested in part to be responsible for the resistance to proteasome inhibitors in patients with various cancers, especially in patients with relapsed and/or refractory multiple myeloma [36].