GSTM1 and anemia (phenotype): Patients in the AMP group were more likely to have anemia (for Hb less than reference value, 9.7% versus 5.4%, P = 0.012), smaller tumor lesions (for tumor size ≤ 7 cm, 94.8% versus 91.4%, P = 0.036), undergo partial nephrectomy (72.7% versus 54.3%, P < 0.001) and adopt transperitoneal approach (7.0% versus 4.1%, P = 0.045).