Three proteins were found down-regulated and 7 proteins up-regulated in PC3PCA+ cells compared to PC3NC cells,including GRP78.Higher GRP78 was also found in PCa clinical specimens.This study confirmed that in PCa, PCA3 plays a pro-cancer role through promoting cell proliferation, migration and invasion while inhibiting cell apoptosis. This process might involve the up-regulation of GRP78.GRP78 was also reported to be preferentially expressed in the camptothecin (CPT)- resistant PC3 prostate cancer cell line in comparison to the CPT-sensitive LNCaP prostate cancer cell line, which indicated its involvement in chemotherapy resistant in PCa.