GSTM1 and anemia (phenotype): In one study (Cella, 1997), assessment of QoL based on the FACT-An showed that patients with Hb levels >12 g dL−1 had significantly less fatigue, fewer non-fatigue anaemia symptoms, better physical and functional well-being, and higher overall QoL than those with an Hb level ⩽12 g dL−1 (P⩽0.01 for all).