GSTM1 and cancer: Table 1 lists various recommendations for target Hb. Until 2006, the most consistent finding seemed to be that an Hb level between 11–13 g/dL improved quality of life, without increasing CVD risk [11–16]. Still, as several trials have explored higher Hb targets, outcomes such as more rapid progression of cancers and increased risk of death and serious cardiovascular events have prompted a black box warning on all ESAs [17–19].