The Role of Neutrophil Extracellular Traps (NETs) in the Pathogenesis and Complications of Malignant Diseases

Abstract

It was recently proved that neutrophils and platelets are active participants in some inflammatory processes as well as a number of pathological conditions, including neoplastic diseases and thrombosis. It has been found that circulating neutrophils actively affect the mechanisms of tumour genesis, and along with platelets, act as independent regulators of different complications in infectious and malignant diseases. A few years ago, it was found that neutrophils have the ability to release extracellular traps (called neutrophil extracellular traps or NETs). Thus, neutrophils use both intracellular and extracellular mechanisms to limit inflammatory complications. Several recent studies confirmed that NETs increase considerably in malignant diseases, demonstrating that tumour-induced NETosis is a clinically significant process. It is recognised as an element of tumour biology, as it participates in tumour progression and angiogenesis. Neutrophils and the NETs released from them are stimulators of thrombotic processes in physiological and pathological conditions. Several reports demonstrate the connection between NETs and thrombosis. The presence of NETosis serves as a potential risk factor for thrombotic complications in malignant diseases. This chapter summarises the current knowledge of NETosis and the mechanisms that lead to the formation of NETs, including the role of circulating platelet–neutrophil complexes as regulators of tumour-induced NETosis in malignant diseases.