['Valproic acid (VPA) acts as a specific inhibitor of class I HDACs and it use has been proven to be safe since a long time.', 'In the present study, we investigated the effect of VPA in the combination with pegylated interferon-α (PEG-IFNα) in inhibition of cell proliferation of human pancreatic cancer cell lines.', 'VPA enhanced the effect of PEG-IFNα, and the effect was decreased by the caspase inhibitor. VPA alone and VPA in combination with PEG-IFNα increased the expression of interferon-α receptor and interferon regulatory factor 8.'] Does valproic acid enhance the anti-tumor effect of pegylated interferon-α towards pancreatic cancer cell lines?