In addition, in two independent sample sets of patients with depression, Papakostas et al. (2013) reported high diagnostic performance and sensitivity and specificity >80% for nine biomarkers (alpha1 antitrypsin, apolipoprotein CIII, brain-derived neurotrophic factor, cortisol, epidermal growth factor, myeloperoxidase, prolactin, resistin, and soluble tumor necrosis factor-alpha receptor type II). Here, MPO is linked to depressive symptom measurement.