The most recent National Comprehensive Cancer Network NCCN guidelines [9] state that RBC transfusions should be considered in patients with symptomatic anemia, high-risk patients (such as those receiving high-dose chemotherapy or radiation with a cumulative decrease in Hb levels), or asymptomatic patients with comorbidities (such as heart disease or cerebral vascular disease) rather than those based on a specific threshold value of Hb. The gene discussed is GSTM1; the disease is anemia (phenotype).