Chau et al. [12] conducted an experiment in which different types of leukemia cell lines were treated with ATO and ATO + azacytidine, and the intracellular arsenic, AQP9 expression, and apoptosis rates were detected; the results showed that intracellular arsenic contents and AQP9 expression in the combined treatment group were higher than those in the ATO alone group. This evidence concerns the gene AQP9 and leukemia.