PADI4 and neoplasm: Neutrophil peptidylarginine deiminase 4 (PAD4) is critical for NET formation, and the use of pharmacological inhibitors of PAD4 can block NET formation and the colonization of cancer cells in the PMN.361,362 For example, the PAD4 isozyme-selective small molecule inhibitor JBI-589 reduces CXCR2 expression and prevents neutrophil chemotaxis, effectively inhibiting cancer metastasis.363 Recent studies have exploited the advantages of neutrophil chemotaxis and depletion of tumor-secreted factors to target PMN.