Notably, the last published NCCN guidelines (Rodgers et al., 2017) indicate that RBC transfusions should be considered not on the basis of a specific threshold value of Hb but in patients with symptomatic anemia, in high risk patients (e.g., those undergoing high-dose chemo-or radiotherapy with cumulative decrease of Hb levels) or asymptomatic patients with comorbidities (e.g., heart disease, COPD, cerebral vascular disease). This evidence concerns the gene GSTM1 and chronic obstructive pulmonary disease.