Immunotherapy in Triple-Negative Breast Cancer: From Molecular Mechanisms to Precision Medicine-Overcoming Resistance and Optimizing Clinical Outcomes

Comprehensive Summary

This review takes a deep look at how immunotherapy is being used in triple-negative breast cancer (TNBC), a subtype that lacks estrogen, progesterone, and HER2 receptors and has historically been harder to treat. The authors walk through the underlying biology that makes TNBC both immunogenic and, at times, resistant to immune-based therapies. They discuss how immune checkpoint inhibitors—particularly those targeting the PD-1/PD-L1 axis—have changed the treatment landscape, especially when combined with chemotherapy. At the same time, they highlight why not all patients benefit. Mechanisms of resistance, such as immune evasion within the tumor microenvironment, low tumor-infiltrating lymphocytes, and adaptive immune suppression, are explored in detail. The article emphasizes the importance of biomarkers like PD-L1 expression, tumor mutational burden, and immune gene signatures to better predict response and refine patient selection. Overall, it frames immunotherapy in TNBC as promising but still evolving toward a more personalized approach.

Outcomes and Implications

For oncologists and researchers, this review underscores that immunotherapy in TNBC is no longer experimental—it is part of standard treatment in selected settings—but optimizing its use remains a major challenge. The variability in response makes precision medicine essential; clinicians cannot rely on a one-size-fits-all model. Identifying which patients are most likely to benefit from checkpoint inhibitors, understanding resistance pathways, and designing rational combination therapies will be key to improving survival outcomes. The article also points toward the need for continued biomarker development and clinical trial innovation to refine treatment sequencing and overcome immune escape. Ultimately, it signals a shift in TNBC management from purely cytotoxic strategies to immune-guided, biology-driven care.