To evaluate the clinical relevance of NETs in CRCs, we examined the expression of neutrophil markers (i.e., MPO, MMP-9 and NE) and a marker of NETs, citrullinated histone H3 (Cit-H3), via the immunohistochemical (IHC) analysis of 133 patients with stage I, II and III CRC who underwent curative resection. This evidence concerns the gene MPO and colorectal carcinoma.