AQP9 and lung cancer: AQP9 was shown to increase the uptake and toxicity of arsenic in lung cancer and leukemia cells [15,27]. Similarly, overexpression of AQP9 in both AsHepG2 (Figures 2A, 2B) and HepG2 (Figures 2C, 2D) cells by pcDNA3-AQP9 resulted in enhanced intracellular arsenic than control cells (Figures 2A-2D).