MMP9 and neoplasm: The suppression of T cell activity by neutrophils represents a critical mechanism underlying tumor immune escape, with distinct mechanisms observed in different tumor types: in colorectal cancer, N2-polarized neutrophils promote immune evasion by activating latent TGFβ via MMP9, thereby suppressing the function of tumor-infiltrating T cells [127]; in ovarian cancer, these TANs mediate IL-8-dependent immunosuppression (suppressing CD8+ T cells) through the Jagged2 signaling pathway [128].