False positive identification of expression sites due to antibody cross-reactivity has been reported in a study where, in addition to using Aqp9 knockout mice, a systematic analysis of the AQP9 expression within the Human Protein Atlas project tissue repository, including a large spectrum of normal and cancer tissues in addition to cell lines and primary cells, was run by shotgun RNA sequencing and protein immunohistochemistry [76]. This evidence concerns the gene AQP9 and cancer.