MPO and chronic obstructive pulmonary disease: In 2021, Suzuki et al. evaluated the plasma proteome using an aptamer-base affinity proteomic platform (SOMAscan®) in 34 subjects with stable COPD and 51 subjects with asthma, detecting 1238 proteins within which stress markers were found, such as myeloperoxidase (MPO), heme oxygenase 2 (HMOX2), superoxide dismutase (Cu-Zn) (SOD1), peroxiredoxin-1 (PRDX1), and glutathione-S-transferase P1 (GSTP1) [61].