Therefore, compared with reticulocyte indices, Hb is not a sensitive index in anemia diagnosis, thus some cancer patients may be with normal Hb and decreased reticulocyte generation reflected by the decreases of RHE and MRV levels, which may cause the similar overall levels of RHE and MRV between anemia and non-anemia patients classified by Hb. The gene discussed is GSTM1; the disease is anemia (phenotype).