1. Patient had prior treatment with an HDAC inhibitor (e.g., depsipeptide or NSC-630176, MS 275, LAQ-824, PXD-101, LBH589, MGCD0103, CRA024781, etc). Patients who have received compounds with HDAC inhibitor-like activity, such as valproic acid, as anti-tumor therapy should not enroll in this study. Patients who have received such compounds for other indications, e.g. valproic acid for epilepsy, may enroll after a 30-day washout period.