To assess whether the increase in circulating H3Cit seen in cancer patients reflected a systemic NET burden, we compared the number of peripheral neutrophils, portion of peripheral neutrophils positive for intracellular H3Cit, plasma markers of neutrophil activation, neutrophil elastase (NE) and myeloperoxidase (MPO) known to be released with NETs [22], and MPO-DNA complexes. Here, MPO is linked to cancer.