Such pleiotropism is reflected by the highly variable and tumor-dependent prognostic role of PERK and Nrf2 in human tumors: mutations in specific oncogenes or oncosuppressor genes, factors related to the tumor micro-environment and immune-system anti-tumor activity, different treatments used in patients likely explain the great variability linking PERK/Nrf2 expression and clinical outcome. The gene discussed is NFE2L2; the disease is neoplasm.