This summary will use Panobinostat (LBH589) in patients with neuroendocrine tumors to see how the patient's tumor responds to panobinostat. Additionally, this study will examine how long it takes neuroendocrine tumor patient's cancer to progress while taking the drug and examine the overall survival of patients using panobinostat. Also, the study will examine the toxicity and tolerability of panobinostat in the patient population. Finally, this study will look at the effect of panobinostat on Notch 1 signaling before and after treatment with panobinostat.