We have not investigated the effect of vorinostat on signal transduction pathways leading to angiogenesis and/or metastasis in our preclinical models; however, several reports have clearly shown that HDAC-Is, including vorinostat, block tumour invasion and metastasis as well as tumour-induced angiogenesis (Kim et al, 2004; Qian et al, 2006; Shankar et al, 2009). This evidence concerns the gene HDAC9 and neoplasm.