Ubenimex, also known as bestatin, is a dipeptide inhibitor of aminopeptidases such as aminopeptidase N/CD13. Bestatin displays efficacy in the treatment of lung cancer. This compound exhibits anticancer chemotherapeutic, immunomodulatory, and analgesic activities. Bestatin enhances differentiation of acute promyelotic leukemia (APL) cells. Additionally, bestatin enhances proliferation of bone marrow macrophage progenitor cells and formation of CFU-GM colonies. This compound also inhibits catabolism of opioid endopeptides.