In grade 4 neutropenia, cancer stage III and basal Hb < 12 g/dL were significant risk factors (cancer stage III: OR 8.90, 95% CI 3.74–21.07; basal Hb < 12 g/dL: OR 2.23, 95% CI 1.14–4.38). The gene discussed is GSTM1; the disease is Decreased total neutrophil count.