HSPA5 and neoplasm: Moreover, an acidic tumor microenvironment was demonstrated to induce ROS-mediated ER stress and upregulate ER stress-related proteins, such as p-PERK, p-eIF2α, DDIT3, spliced X-box binding protein 1 (XBP1s), and glucose-regulated protein 78 (GRP78), which promote both autophagy and cell survival, in NSCLC in vitro model [35,36].