In 2012 a Cochrane meta-analysis assessing 91 trials with 20,102 patients found that if ESAs are used correctly for the therapy of chemotherapy-induced anemia as well CRA only if Hb is below 12 g/dl, no increase in overall mortality and on-study mortality have been observed (Tonia et al., 2012). This evidence concerns the gene GSTM1 and anemia.