GSTM1 and cancer: Restrictive transfusion trigger (i.e., Hb 70–75 g/L) was shown to be safe compared to liberal transfusion trigger (i.e., 90–100 g/L) by randomized controlled trials in different populations of patients: the critically ill [26], cardiac surgery patients [27,28], orthopedic surgery patients with cardiac risk factors [29], septic patients [30], and those with malignant tumors [31].