FGF2 and neoplasm: Furthermore, PERK facilitates angiogenesis and tumor development not only by upregulating the expression of VEGF, interleukin-6 (IL-6), fibroblast growth factor 2 (FGF2), platelet-derived growth factor receptor β (PDGFRB), and type I collagen inducible protein (VCIP), which are involved in the generation, growth, and stabilization of vessels, but also by downregulating anti-angiogenic cytokines [143,148].