Anemia due to a chronic disease, such as cancer, results from the dysregulation of iron homeostasis induced by inflammatory cytokines such as interleukin-6 (IL-6) and interferon gamma (IFN-γ) as well as the suppression of erythropoietic activity, and it associates with poor OS among cancer patients [41–43]. The gene discussed is IL6; the disease is anemia (phenotype).