HDAC6 and cancer: As the catalytic activity of HDAC6 is modulated by protein–protein interactions and post-translational modifications that may also allosterically control the catalytic domains of HDAC6 [14], the inhibition of HDAC6 in cancer with small molecule inhibitors requires consideration of the function it performs in the cancerous environment and if its expression in a tumour correlates with its deacetylase activity.