STC2| Zeiger et al. discovered a cell-internal function of the glycoprotein Stanniocalcin 2 (STC2), whereof aberrant expression patterns have been identified in a series of cancer types, in addition to an apparent role thereof in metastasis formation, as a negative modulator of SOCE if residing in the ER lumen that contrasts the well-established endocrine regulation of phosphate as well as Ca2+ homeostasis by secreted fish STC. Here, STC2 is linked to cancer.