Arsenic in the treatment of newly diagnosed acute promyelocytic leukemia: current status and future research direction.

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia. In past decades, intensive studies on the biology and treatment of this disease have resulted in a remarkably thorough understanding of its pathogenesis and improvement of treatment outcomes. In particular, the introduction of all-trans retinoic acid to conventional chemotherapy improved dramatically the remission and survival rates of APL patients and consequently became the major treatment modality for it. In the last decade, the groundbreaking development of arsenic further improved the survival rate of APL patients. As the most active agent in APL, arsenic directly degrades the PML-RARα fusion transcript, leading to the differentiation and apoptosis of leukemia cells and the potential eradication of APL leukemiainitiating cells (LICs), thus making the disease a potentially curable type of leukemia. More notably, the recent development of oral arsenic compounds may further enhance not only clinical outcomes but also the convenience of patients, which may dramatically change the APL clinical scenario in the near future.