NETs in cancer

Many aspects of neutrophil hyperactivity and its role in numerous immune responses still remain a mystery. A new neutrophil mechanism was discovered recently, i.e., the formation of neutrophil extracellular traps (NETs). These structures, composed of DNA strands and neutrophil granule proteins, are an element of the non-specific immune response and bind pathogens to prevent their spread and ensure increased local concentrations of toxic factors. Research on this phenomenon shows that tumor-associated neutrophils (TANs) also form and release NETs. Reports on the role of NETs in the course of cancer are scarce, and the opinions on the involvement of extracellular traps in the disease are divided, indicating a dual function. There is speculation about the anti-cancer properties of NETs connected with direct killing of cancer cells or stimulation of the immune system. On the other hand, the trap structures might promote migration and immune escape of cancer cells or constitute a physical barrier between cancer cells and immune-competent cells. This article summarizes our knowledge about the proven roles of NETs in the course of cancer with particular focus on the significance of NETs as prognosis biomarkers in the course of the neoplastic process and their potential use in therapy.