4. Patient has had prior treatment with an HDAC inhibitor (e.g., romidepsin (Depsipeptide), NSC-630176, MS 275, LAQ-824, belinostat (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 under neurological supervision.