To investigate the role of AQP9 in the combinational effect of G-CSF and ATO on AML cells, we interfered the expression of AQP9 by siRNA in THP-1 cells (mock siRNA as negative control) and then treated with the cells with ATO alone or G-CSF/ATO in combination (the vehicles as control). Here, AQP9 is linked to acute myeloid leukemia.