Neutrophil Dynamics in Response to Cancer Therapies.

Neutrophils are increasingly recognized as key players in the tumor microenvironment (TME), displaying functional plasticity that enables them to either promote or inhibit cancer progression. Depending on environmental cues, tumor-associated neutrophils (TANs) may polarize toward antitumor "N1" or protumor "N2" phenotypes, exerting diverse effects on tumor growth, metastasis, immune modulation, and treatment response. While previous studies have focused on the pathological roles of TANs in cancer, less attention has been given to how cancer therapies themselves influence the behavior of TANs. This review provides a comprehensive synthesis of current knowledge regarding the dynamics of TANs in response to major cancer treatment modalities, including chemotherapy, radiotherapy, cell-based immunotherapies, and oncolytic viral and bacterial therapies. We discuss how these therapies influence TAN recruitment, polarization, and effector functions within the TME, and highlight key molecular regulators involved. By consolidating mechanistic and translational insights, this review emphasizes the potential to therapeutically reprogram TANs to enhance treatment efficacy. A deeper understanding of context-dependent TAN roles will be essential for developing more effective, neutrophil-informed cancer therapies.