Among the various immunomodulatory strategies tested in combination with OVs, HDACIs have been explored as a means to enhance virus-mediated oncolysis via suppression of the tumor cell anti-viral IFN response following infection.16, 31 However, HDAC inhibition has a wide range of consequences, and a recent study demonstrated, using cDNA arrays, that the expression of 10%–20% of genes was altered following treatment with HDACIs.48 This evidence concerns the gene HDAC9 and neoplasm.