AQP1 and neoplasm: Indeed, gene expression profiling of AtT-20 cells (mouse corticotrope tumor cells) overexpressing PAM showed increased expression of Aquaporin 1 (Aqp1) and secretory leukocyte peptidase inhibitor (Slpi), affecting formation and proteome content of secretory granules28–30, both of which were validated to be regulated by PAM sfCD24.