The UPR consists of three main signaling pathways mediated by the sensors IRE1, PERK, and ATF6. These pathways help cancer cells survive under stressful conditions by enhancing protein folding capacity, degrading misfolded proteins, and adapting cellular metabolism. However, chronic activation of the UPR can also contribute to tumorigenesis by promoting cell proliferation, angiogenesis, and resistance to apoptosis.
