HSPA5 and breast cancer: ER stress triggers the UPR, resulting in elevated expression of GRP78 and its translocation to the cell surface.[5b] Numerous studies support the role of csGRP78 as a hallmark of cancers, including ovarian, prostate, brain, breast cancer, myeloma, melanoma, and lymphoma, as well as other stressed cells.[5, 14] To further confirm GRP78 as a potential target for cancer therapy, the expression of GRP78 was examined via immunohistochemical staining on a tissue microarray encompassing eight different cancer types and their adjacent tissues.