Aronson et al. [36] reported that RBC transfusion in patients with myocardial infarction decreased the risk of mortality if the pre-transfusion Hb level was ≤ 80 g/L (adjusted hazard ratio (aHR): 0.13: 95% CI: 0.03 to 0.65), but the risk was increased if the Hb level was > 80 g/L (aHR: 2.2; 95% CI: 1.5 to 3.3). The gene discussed is GSTM1; the disease is myocardial infarction.