CD66b, NE and MPO, defined as neutrophil markers, had elevated expression in grade IV glioma tissues compared with grade II or grade III glioma tissues (Figure 1E, CD66b: Grade II vs. Grade III: P = 3.00E-04, Grade II vs. Grade IV: P = 2.00E-04, Grade III vs. Grade IV: P = 7.30E-03; NE: Grade II vs. Grade III: P = 2.46E-02, Grade II vs. Grade IV: P = 2.90E-03, Grade III vs. Grade IV: P = 4.88E-02; MPO: Grade II vs. Grade III: P = 6.90E-03, Grade II vs. Grade IV: P = 6.00E-04, Grade III vs. Grade IV: P = 1.51E-02). The gene discussed is MPO; the disease is central nervous system cancer.