‐use supportive measures (i.e., G‐CSF in primary prophylaxis, treatment of underlying anemia, prevention of mucositis);‐avoid using cytotoxic chemotherapy if risk of toxicity is higher than 40% and not preventable (i.e., by using prophylactic G‐CSF)‐review and reconcile polypharmacy‐If cytotoxic chemotherapy is highly indicated, use regimens with lower predicted toxicity if possible. The gene discussed is CSF3; the disease is anemia.