Although many studies have reported the potential value of NETs as serum markers for early tumor screening or prognostic prediction, many problems are still waiting to be solved, for instance, challenges persist in accurately detecting key components of NETs, such as circulating free DNA (cfDNA), nucleosomes, citrullinated histone H3 (citH3), and NET-related proteins like NE and MPO. Here, MPO is linked to neoplasm.