GSTM1 and anemia (phenotype): Anemia may also cause chemotherapy dose reductions or delays, thereby decreasing relative dose intensity and potentially compromising treatment efficacy.According to Western clinical guidelines, including those issued by the European Society for Medical Oncology (ESMO) [2] and the National Comprehensive Cancer Network (NCCN) [3], iron supplementation is recommended for patients with mild anemia, whereas erythropoiesis-stimulating agents (ESAs) are the mainstay of treatment for patients with hemoglobin (Hb) levels below 10 g/dL.