STAT1 and acute promyelocytic leukemia: Pretreatment with valproic acid (VPA) suppressed the transcription of IFN-stimulated anti-viral genes, such as signal transducers and activators of transcription 1 (STAT1), protein kinase R (PKR) and promyelocytic leukemia (PML), thereby increasing HSV gene expression, propagation and cytotoxicity [135].