NETosis in pulmonary pleomorphic carcinoma

Pulmonary pleomorphic carcinoma (PC) is a rare non-small-cell lung carcinoma (NSCLC) with a poor prognosis, characterized by tumor necrosis (TN). NETosis is a form of neutrophil-specific cell death, which is morphologically characterized by prominent neutrophil infiltration and cell detritus in the necrotic foci. Seventy-six patients with pulmonary PC who underwent complete resection were enrolled. Tumor necrosis was evaluated using digitally scanned resected specimens. The regions of NETosis were quantified using citrullinated histone H3 (citH3)- and myeloperoxidase-positive regions. We examined the association between the NETosis area and the prognostic outcomes and assessed the correlation between the NETosis area and systemic inflammation. Tumor necrosis was observed in 70 patients (92%). In all the cases, the TN region was accompanied by a citH3-positive region. The patients with high NETosis area (n = 54) had significantly shorter overall survival than those with low NETosis area (n = 16) (p = 0.013). Furthermore, a high NETosis area was an independent poor prognostic factor in the multivariate analyses. Systemic inflammatory markers, including C-reactive protein (CRP), CRP-to-albumin ratio, and neutrophil-to-lymphocyte ratio, were significantly higher in patients with high NETosis area than in those with low NETosis area. Furthermore, the levels of these inflammatory markers were significantly decreased postsurgery. This study shows that in surgically resected pulmonary PC, patients with high NETosis areas have higher systemic inflammation and worse prognosis.