As shown in Figure 7A, the phosphorylation of ERK1/2 was significant suppressed in AQP9 siRNA-transfected cells compared with that in control cells, Moreover, U0126 was used to suppress the activation of the ERK, in accordance with the result, U0126 treatment inhibited the invasion of PC-3 cells (Figure 7B), suggesting that AQP9 is involved in the activation of the ERK pathway in prostate cancer cells. Here, AQP9 is linked to prostate cancer.