Neutrophil Extracellular Traps in Tumor Metastasis: Pathological Functions and Clinical Applications

Neutrophil extracellular trap (NET) formation is an ability of neutrophils to capture and kill pathogens by releasing chromatin scaffolds, along with associated cytotoxic enzymes and proteases, into the extracellular space. NETs are usually stimulated by pathogenic microorganisms and their products, surgical pressure or hypoxia. Interestingly, a number of recent studies suggest that tumor cells can induce NET formation, which in turn confers tumor cell malignancy. Notably, emerging studies indicate that NETs are involved in enhancing local invasion, increasing vascular permeability and facilitating immune escape and colonization, thus promoting tumor metastasis. In this article, we review the pivotal roles of NETs in the tumor metastasis cascade. We also recapitulate the potential of NETs as a cancer prognostic biomarker and therapeutic target.