In the very beginning, we expected that 108-B6 and 4A68 recognized the short N-terminal extracellular domain of PGRMC1 in hPSCs and cancer cells, because the cytoplasmic side of membrane proteins remains on the cytoplasmic side while the luminal side of membrane proteins is exposed on the cell surface even during the process of cell surface translocation32,33. Here, PGRMC1 is linked to cancer.