Since AQP5 is a peroxiporin, we were interested in whether overexpression of AQP5 affects the intracellular generation of ROS upon the exogenous addition of a range of H2O2 concentrations (0, 2.5, 5, 10, 20, 40, 70, and 100 μM) in the tested breast cancer cell lines. This evidence concerns the gene AQP5 and breast cancer.