Recent clinical studies have demonstrated the chemotherapeutic efficacy of VPA for the treatment of several types of cancer, including acute myeloid leukemia, myelodysplastic syndromes [3], and solid breast and cervix tumors [4].VPA is a histone deacetylase (HDAC) inhibitor that alters gene expression, thereby modulating processes such as cell growth, differentiation and apoptosis [5,6].