Beyond conventional therapies: the evolution of targeted agents and immunotherapies in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a clinically aggressive and molecularly heterogeneous subtype defined by the absence of estrogen receptor, progesterone receptor, and HER2 expression. Chemotherapy remains the mainstay of treatment, but recent advances in immune checkpoint inhibitors, DNA damage response-targeted therapies, antibody-drug conjugates, and small-molecule inhibitors have expanded therapeutic options. Despite these developments, clinical outcomes are still limited by tumor heterogeneity, suboptimal biomarker selection, resistance, and treatment-related toxicity. In this review, we summarize current and emerging therapeutic strategies for TNBC with a focus on their underlying biological rationale. We highlight key approaches targeting DNA repair deficiency, immune regulation, oncogenic signaling pathways, and antigen-directed therapies, and discuss their clinical development and application. We also address the role of molecular subtyping and biomarkers in guiding treatment selection, as well as the challenges posed by resistance and limited durability of response. Overall, this review provides an updated overview of TNBC treatment strategies and discusses ongoing challenges and future directions toward more effective and individualized therapies.