Following identification of the erythropoietin gene, ESAs were soon being mass-produced, reducing anemia in the same manner as the human protein erythropoietin, i.e., by stimulating the proliferation and differentiation of red blood cell progenitors (burst-forming unit-erythroids and colony-forming unit-erythroids), and preventing apoptosis (Elliott et al., 2008; Lodish et al., 2010). The gene discussed is EPO; the disease is anemia.