Modeling the management of patients with human epidermal growth factor receptor 2-positive breast cancer with liquid biopsy: the future of precision medicine

Purpose of reviewIn the evolving landscape of human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) management, liquid biopsy offers unprecedented opportunities for guiding clinical decisions. Here, we review the most recent findings on liquid biopsy applications in HER2-positive BC and its potential role in addressing challenges specific to this BC subtype.Recent findingsRecent studies have highlighted the significance of liquid biopsy analytes, primarily circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs), in stratifying patients' prognosis, predicting treatment response, and monitoring tumor evolution in both early and advanced stages of BC. Liquid biopsy holds promise in studying minimal residual disease to detect and potentially treat disease recurrence before it manifests clinically. Additionally, liquid biopsy may have significant implication in the management of brain metastasis, a major challenge in HER2-positive BC, and could redefine parameters for determining HER2 positivity. Combining ctDNA and CTCs is crucial for a comprehensive understanding of HER2-positive tumors, as they provide complementary insights.SummaryResearch efforts are needed to address analytical challenges, validate, and broaden the application of liquid biopsy in HER2-positive BC. This effort will ultimately facilitate its integration into clinical practice, optimizing the care of patients with HER2-positive tumors.