AQP5 immunolabeling of SG sections from several animal models for SS and from some SS patients revealed an aberrant expression and/or localization of AQP5 in acinar cells, with a predominant basolateral membrane and/or intracellular localization instead of a typical normal apical membrane localization [56,77,78,79,80,81]. The gene discussed is AQP5; the disease is synovial sarcoma.