AQP1 and neoplasm: Based on these data, and considering the previously demonstrated increase in VEGF expression in AQP1 siRNA‐treated tumours 30, we here propose a mechanism (Fig. 6) in which the reduced neovessel formation in AQP1 silenced tumours is responsible for hypoxia, documented by HIF‐1α increase, in turn causing VEGF increase, as expected.