 Trisenox arsenic trioxide is a newly-approved pharmaceutical grade arsenic compound antineoplastic agent which has demonstrated clear activity in anthracycline- and all-trans retinoic acid-resistant acute promyelocytic leukemia. Trisenox also has US Compendium listing for acute leukemia, chronic myelogenous and lymphocytic leukemias, myelodysplasia, multiple myeloma, and hepatocellular carcinoma HCC. Similar to the taxanes and vinca alkaloids, Trisenox appears to interfere with microtubule function, which triggers cell differentiation, and induces programmed death, or apoptosis. The mechanism of this is unclear, but appears to involve activation of caspases and the down-regulation of the BCL-2 oncogene. Trisenox also interfere with the function of NF-kappaB, leading to inhibition of cellular proliferative signals, apoptosis, and inhibition of tumor angiogenesis. 