GSTM1 and anemia (phenotype): Perioperative anemia should be addressed if surgical bleeding is expected to be significant.[18] The rationale for anemia correction is that improving the oxygen-carrying capacity of the blood helps prevent clinical symptoms secondary to tissue hypoxia, including fatigue, shortness of breath, chest pain, weakness, loss of appetite, and headache.[19] Although ABT is the most common method used to increase Hb levels, it is associated with adverse effects in patients with EBSs.