HSPA5 and ovarian cancer: Moreover, the use of GRP78 or PAR-4 antibodies in culture medium to interfere within the interaction between secreted PAR-4 and membranous GRP78 does not impact PAR-4 induced apoptosis in taxol-treated cells suggesting that secreted PAR-4 does not play a significant role in “apoptosis-sensitizing” function of ovarian cancer cells.