eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2026-10-10 23 3 59969 article Chinni Krishna Khandavalli 1 Jagannadham Nuthana Yashwanth 1 Erothi Balakoti 1 Donka Devi 1 Pharmacology Division, AU College of Pharmaceutical Sciences, Andhra University, Visakhapatnam, India Triple-negative breast cancer (TNBC) is a biologically heterogeneous and clinically aggressive breast cancer subtype in which therapeutic resistance often emerges despite initial chemosensitivity. Conventional tissue biomarkers remain essential for diagnosis and initial treatment selection, but they provide limited information about temporal tumour evolution, molecular residual disease, clonal resistance and patient-specific toxicity risk. Liquid biopsy and pharmacogenomics offer complementary precision-oncology tools for addressing this gap. Circulating tumour DNA (ctDNA) can track tumour burden, molecular response and acquired resistance; circulating tumour cells (CTCs) can reveal viable metastatic phenotypes and epithelial–mesenchymal plasticity; extracellular vesicles and circulating RNAs may reflect tumour–stromal communication and adaptive resistance signalling. Pharmacogenomics adds a second layer by identifying tumour vulnerabilities such as BRCA1/2-associated homologous recombination deficiency and host determinants of drug toxicity such as DPYD and UGT1A1 variation. This review synthesizes mechanistic and translational evidence supporting integrated liquid biopsy–pharmacogenomics approaches in TNBC. Current clinical utility is strongest for BRCA1/2-directed PARP inhibition, PD-L1-guided immunotherapy in eligible settings, DPYD-guided fluoropyrimidine safety, UGT1A1-informed sacituzumab govitecan toxicity surveillance and ctDNA-based molecular residual disease risk assessment. However, most liquid-biopsy-guided treatment adaptation remains investigational. Future progress requires prospective trials demonstrating that biomarker-guided escalation, de-escalation or therapy switching improves survival, reduces toxicity or prevents molecular relapse. https://www.biotech-asia.org/vol23no3/integrative-liquid-biopsy-and-pharmacogenomics-for-monitoring-treatment-response-and-guiding-precision-therapy-in-triple-negative-breast-cancer-a-mechanistic-and-clinical-review/ BRCA1/2; DPYD; Immunotherapy; Molecular residual disease; Pharmacogenomics;Poly (ADP-ribose) polymerase (PARP) inhibitors; Precision oncology; Sacituzumab govitecan; UGT1A1