ORP150 (150KDa Oxygen-regulated Protein) is a member of the heat shock protein/stress protein family and has a pivotal role in cytoprotective cellular mechanisms triggered by oxygen deprivation. This protein has also been described as a molecular chaperone, induced by various environmental and physiological stimuli, and participates in protein folding in the endoplasmic reticulum. Furthermore, ORP150 is up-regulated in tumors and, in breast tumors, may be associated with tumor invasiveness.