The antigen-processing genes in many metastatic cancers are under epigenetic control and several pan-HDAC inhibitors have been shown to upregulate APM components, including TSA, Panobinostat, Valporic and Depsipeptide (Setiadi et al., 2005a; Setiadi et al., 2007a; Setiadi et al., 2008a; Ma et al., 2009). Here, HDAC9 is linked to metastatic malignant neoplasm.