PRECISION MEDICINE IN ONCOLOGY: TAILORING TREATMENTS THROUGH BIOMARKERS

Abstract

Precision oncology aligns therapy with the molecular profile of a patient’s tumor and, when relevant, germline risk. Over three decades, companion diagnostics and agnostic approvals have reshaped standards of care in multiple malignancies. Biomarkers now span proteins (e.g., PD-L1), single-gene alterations (EGFR, ALK), complex genomic signatures (MSI-H/dMMR, HRD, TMB), and dynamic measures from liquid biopsy (ctDNA/MRD). This article reviews biomarker taxonomy and clinical utility; compares assay platforms (IHC, FISH, PCR, targeted NGS, WES/WGS, and liquid biopsies); summarizes evidence from basket/umbrella/platform trials; and discusses implementation in diverse health-system contexts including LMICs. We highlight governance, reimbursement, and equity considerations, and chart emerging directions—single-cell and spatial omics, multi-modal AI predictors, and ctDNA-guided treatment adaptation. Precision oncology requires rigorous analytical/clinical validation, multi-disciplinary decision-making, and continuous evidence generation through learning health systems to deliver reproducible benefit at scale.