HSPA5 and neoplasm: Likewise, the activation of other ERS signal transducers, IRE1 and ATF6, can also favor tumour growth and enhance cell tolerance to stress by activating the mRNA of transcription factor X-box-binding protein 1 (XBP-1) and upregulating expression of major ER chaperones (including Grp78) and ERAD components [20, 21].