Importantly, the rescue effects of FG‐4592 on anemia‐related and iron‐related parameters, especially duodenal Hif2α, Fpn mRNA, and protein levels in 5‐FU treated control mice could not be replicated in Hif2α‐IKO mice (Figure 7R–T; Figure S10D, Supporting Information). The gene discussed is EPAS1; the disease is anemia.