Tumor cells can adapt to hypoxic conditions by producing erythropoietin (EPO), switching from aerobic to anaerobic metabolism, downregulating DNA repair pathways, enlisting the assistance of stromal cells, and upregulating protooncogenes as well as hypoxia-inducible factor (HIF) 1 and HIF 2 [76]. The gene discussed is EPO; the disease is neoplasm.