Anti-neutrophil antibodies (anti-MPO-ANCAs) are associated with poor prognosis in breast cancer patients.

Anti-neutrophil antibodies are capable of activating neutrophils in sterile environments, releasing extracellular traps containing myeloperoxidase (MPO) and anti-MPO antibodies (MPO-ANCAs or anti-MPO-ANCAs), which have been implicated in the pathogenesis of several diseases. The present study evaluated systemic and tumor tissue levels of anti-MPO-ANCAs breast cancer patients, and its relation to clinicopathological characteristics. Anti-MPO-ANCAs were measured in serum and tissue samples of 150 patients by enzyme-linked immunoassay. Samples were pooled according to clinicopathological characteristics of patients. Higher anti-MPO-ANCAs levels were detected in groups presenting negative clinicopathological characteristics, such as high histological grade tumors and risk factors such as body mass index, menopausal status and early onset at diagnosis. The present data highlights anti-MPO-ANCAs as associated to poor prognosis in breast cancer, a role beyond its actually discussed role in autoimmunity and vasculitis.