In particular, proinflammatory cytokines (e.g., TNF-α, IL-1, IL-6), released by the cancer and activated immune cells in response to malignancy, may result in anemia by inducing changes to iron balance, inhibition of erythropoiesis, impairment of EPO synthesis and activity, reduction of erythrocytes lifespan and changes of energy metabolism (Means, 1995). Here, EPO is linked to anemia (phenotype).