GSTM1 and anemia: Among the pre-selected ET patient cohort, 22.8% (n = 113) showed splenomegaly (> 11 cm diameter), and 1% (n = 5) by palpation; 80.4% (n = 398) had elevated LDH (above upper normal limit), 3.6% (n = 18) had circulating blasts, 27.1% (n = 134) elevated leukocyte values (> 11Gpt/l), 12.5% (n = 62) mild anemia (Hb ≥ 10 g/dl and < 12 g/dl) and 2% (n = 10) severe anemia (Hb < 10 g/dl).