SGK1 and breast carcinoma: Stimulated by serum in MDA231 cells derived from human breast cancer [113] or using morpholino oligonuleotides against SGK1 in Xenopus laevis oocyte [114], SGK1 was demonstrated to function upstream of IKKβ; therefore, SGK1 could modulate the activities of Nedd4-2 in concert with IKKβ, contributing to the enhanced accumulation of ENaC channel at the apical membrane [98,111].