HDAC9 and cancer: A comparison of the binding interactions was carried out, for example, of the synthetic analogue; (2E,2′E)-N,N′- (disulfanediylbis(ethane-2,1-diyl))bis(2-(hydroxyimino)-3-(2,4-dichlorophenyl)propanamide, which showed better HDAC inhibitory activity than PsA and comparable antiproliferative activity with psammaplin A (15) against all four tested cancer cells (Wen et al., 2016).