HDAC9 and cancer: SAHA was significantly less toxic than TSA, consistent with similar differences between their relative potencies for killing cancer cells (Marks and Breslow, 2007) and parasites (Andrews et al., 2009) and inhibiting inflammatory diseases (Halili et al., 2009), and is simply due to differences in their relative cell permeabilities coupled with their relative affinities for HDAC enzymes inside cells (Gupta, 2012).