HSPA5 and prostate cancer: Importantly, GRP78: 1) is highly active in osteoblastic, androgen-independent prostate cancer [14], suggesting that it might play a pivotal role in the interaction of PCa cells with OSB, 2) plays a critical role in the adhesion and invasion of hepatocellular carcinoma [15] and MM [16], 3) can mediate resistance against cytotoxic chemotherapy in PCa cells [17], and 4) is overexpressed in a quiescent MM cell sub-population resistant to treatment [18, 19].