A study by Zhu [111] that analyzed the mRNA of AQPs indicated that high AQP0, AQP1, AQP2, AQP4, AQP6, AQP8, AQP10, and AQP11 mRNA expression levels were significantly associated with improved relapse-free survival (RFS) and that, in contrast, AQP3 and AQP9 were associated with a shorter RFS in breast cancer patients, indicating that these two genes may serve as targets for future chemotherapy. Here, AQP2 is linked to breast cancer.