Phenylbutyrate Plus Azacitidine in Treating Patients With Acute Myeloid Leukemia, Myelodysplasia, Non-Hodgkin's Lymphoma, Multiple Myeloma, Non-small Cell Lung Cancer, or Prostate Cancer

RATIONALE: Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Combining more than one chemotherapy drug may kill more cancer cells. PURPOSE: Phase II trial to study the effectiveness of phenylbutyrate plus azacitidine in treating patients who have acute myeloid leukemia, myelodysplasia, non-Hodgkin's lymphoma, multiple myeloma, non-small cell lung cancer, or prostate cancer.