In a recent study, stratification of 1,109 MF patients by grade of anemia demonstrated that patients with severe (Hb < 8 g/dL or transfusion dependence) and moderate (Hb in the range 8–10 g/dL) anemia had a median survival of 2.1 and 3.4 years, respectively [24]. Here, GSTM1 is linked to anemia (phenotype).