Biomarker Guided Chemotherapy and Immunotherapy Response in Asian Triple-Negative Breast Cancer: A Systematic Review

<ns5:p>Triple-negative breast cancer (TNBC) is an aggressive subtype characterized by the absence of ER, PR, and HER2 expression, with limited therapeutic targets and poor prognosis. Chemotherapy remains the cornerstone of treatment; however, response variability highlights the need for predictive biomarkers. This systematic review aims to evaluate biomarker-guided chemotherapy and immunotherapy responses in Asian TNBC populations. A literature search was conducted in PubMed following PRISMA 2020 guidelines, identifying 31,888 records, of which 7 studies met inclusion criteria. Eligible studies included randomized controlled trials, subgroup analyses, and observational studies assessing chemotherapy alone or combined with immunotherapy in Asian patients, reporting outcomes such as pathologic complete response (pCR), progression-free survival (PFS), and overall survival (OS). Across studies, combination regimens incorporating immune checkpoint inhibitors, particularly pembrolizumab and atezolizumab, demonstrated superior clinical outcomes compared to chemotherapy alone, including higher pCR rates and improved survival metrics. Biomarker analysis revealed that PD-L1 expression consistently predicted improved response to immunotherapy, while homologous recombination deficiency (HRD) was associated with enhanced sensitivity to platinum-based and eribulin regimens. Additional markers, including tumor-infiltrating lymphocytes (TILs) and tumor mutational burden (TMB), were linked to better therapeutic outcomes, whereas elevated microRNA-223 expression correlated with chemotherapy resistance and poorer prognosis. Safety profiles were generally manageable, with expected toxicities such as peripheral neuropathy and hematologic adverse events. These findings support the integration of molecular and immunological biomarkers into clinical decision-making to optimize treatment strategies. In conclusion, biomarker-guided chemo-immunotherapy represents a promising approach to improving outcomes in Asian TNBC patients, emphasizing the importance of precision medicine and the need for standardized biomarker assessment in future studies.</ns5:p>