AQP1 and neoplasm: Among the thirteen higher mammalian AQPs, AQP1 and AQP9 have been associated thus far with stages of the metastatic cascade, including angiogenesis [407], cell migration, cell–matrix interactions, epithelial–mesenchymal transition (EMT), invasion [442], and increased ROS levels associated with oxidative stress and tumor formation [300,405,443].