The Relationship Between Neutrophil Extracellular Traps and CD8+ T Lymphocytes in Cancer: A Comprehensive Review of Current Data

Neutrophil extracellular traps (NETs) are web-like structures composed of decondensed DNA, histones, and proteins released by activated neutrophils. Originally identified as an innate defense mechanism against pathogens, NETs have since been implicated in cancer progression and immune evasion. Within the tumor microenvironment (TME), NETs suppress anti-tumor immunity through multiple mechanisms, including the physical exclusion of CD8+ cytotoxic T lymphocytes from the tumor interior and upregulation of exhaustion markers via checkpoint ligands. This review synthesizes current preclinical and clinical evidence on the interplay between NETs and CD8+ T cells across multiple malignancies, including non-small cell lung cancer, pancreatic ductal adenocarcinoma, cholangiocarcinoma, colorectal cancer, bladder cancer, hepatocellular carcinoma, skin cancer, and penile cancer. Cancer-specific mechanisms of NET-mediated immune suppression are discussed, including IL-8, IL-17, CXCL6, and TGF-β-driven NETosis pathways. Clinical data consistently demonstrate that elevated NET levels correlate with reduced CD8+ T cell infiltration, T cell dysfunction, and worse patient outcomes. Emerging therapeutic strategies targeting this axis are reviewed, including DNase I-mediated NET degradation, Peptidyl arginine deiminase 4 (PAD4) inhibition, CXCR2 blockade, and combination approaches with immune checkpoint inhibitors. These interventions have shown promise in restoring CD8+ T cell cytotoxicity and overcoming immunotherapy resistance in preclinical models. Collectively, the evidence supports the NET-CD8+ T cell axis as a promising prognostic and therapeutic target warranting further clinical investigation.