MPO and lung cancer: Furthermore, patients with early lung cancer had a significantly higher NE levels than patients with COPD (P < 0.01).There were no significant differences of NE and MPO levels in serum and BAL fluid in lung cancer patients with performance status 0–1 when comparing to patients with performance status 2–3 (NE serum 509.51 ± 8.76 ng/mL vs. 528.01 ± 18.45 ng/mL, NE BAL fluid 314.38 ± 8.29 ng/mL vs. 338.21 ± 25.08 ng/mL, MPO serum 297.13 ± 13.00 ng/mL vs. 300.85 ± 18.03 ng/mL, MPO BAL fluid 112.94 ± 14.14 ng/mL vs. 121.72 ± 11.92 ng/mL, P > 0.05).