In addition to up-regulation in cancer cells, GRP78 may also translocate from the endoplasmic reticulum to the cell membrane, where it mediates the transmission of extracellular signals as a membrane receptor, for example, as a receptor for α2-macroglobulin [22] or as a receptor/cofactor for GPI anchor signaling protein Cripto [23]. This evidence concerns the gene CRIPTO and cancer.