Multi-omic, HER2-directed monitoring in metastatic breast cancer through a clinic-ready wearable cytokine biosensor

Background: Immune and inflammatory monitoring in oncology remains limited by intermittent blood sampling that misses early signals of disease activation, treatment-related toxicities, and emerging resistance. Preliminary data from our wearable platform, generated in inflammatory and immune-dysregulation settings, demonstrate that sweat-based cytokine tracking can noninvasively capture dynamic immune changes with high temporal resolution. Building on these foundational results, the overarching goal of our project is to translate this technology into a multi-omic, HER2-directed monitoring strategy for HR+/HER2− and HER2+ metastatic breast cancer (MBC). Methods: To support longitudinal, minimally invasive immune monitoring in metastatic breast cancer, we use a wearable platform designed for real-time assessment outside the clinic. Preliminary benchtop and on-body studies in inflammatory and high-risk cohorts established analytical validity and concordance with reference immunoassays using AI-assisted smartphone analysis. The technology is a flexible, skin-mounted microfluidic sweat patch enabling multiplex colorimetric detection of TNF-alpha, IL-6, IL-1beta, and C-reactive protein. In a HER2-focused extension, this platform will be integrated with longitudinal tumor and blood genomics to expand the biomarker panel and develop AI models linking sweat cytokine dynamics to therapeutic response and resistance in HR+/HER2− and HER2+ metastatic breast cancer. Results: In the preliminary inflammatory disease phase, our device demonstrated clinical readiness for high-frequency immune surveillance, with reliable sweat collection during routine activity, and strong concordance with standard immunoassays. From an engineering standpoint, the device sustained pump-free, capillary-driven flow and generated robust, concentration-dependent cytokine signals with low pg/mL sensitivity, broad linear ranges, and low device-to-device variability. These data directly inform the HER2-MBC project design, including sampling schedules, target ranges, and analytical thresholds for resistance alerts. Conclusions: This wearable device provides first-in-human-like, noninvasive, quantitative cytokine monitoring data in inflammatory disease that serve as critical preliminary evidence for a HER2-directed, multi-omic precision monitoring strategy in MBC. By coupling a validated wearable biosensor with deep molecular profiling in HR+/HER2− and HER2+ MBC, the forthcoming project aims to deliver real-time, sweat-based biomarkers that anticipate resistance, guide adaptive therapy, and reduce reliance on invasive, low-frequency tissue and blood sampling.