HSPA5 and cancer: Inhibition of GRP78 activates the NF-κB pathway, leading to a series of downstream responses, for example, which increase mir-155-5p targeted MDR1 expression which suppresses efflux of 5-FU, leading to the accumulation of 5-FU in cancer cells, activation of Caspase-3 and PARP, and decrease in Bcl-2 but increase in Bad, which in turn causes the cancer cells apoptosis (193).