Abstract PS4-05-02: Rapid and ultrasensitive detection of surgical margin and metastatic lymph node via EpCAM-targeted surface-enhanced Raman scattering biosensor in breast cancer

Abstract Purpose: Breast-conserving surgery (BCS) and sentinel lymph node biopsy (SLNB) are cornerstones of precision treatment for early breast cancer, aiming to balance oncological efficacy with cosmetic and functional preservation. However, current intraoperative margin evaluation and SLNB rely on frozen section pathology, which faces inherent technical limitations, including prolonged procedural time and considerable false-negative rates in detecting micro-metastases. To address these challenges, we developed a novel surface-enhanced Raman scattering (SERS) biosensor, targeting breast cancer-specific biomarker epithelial cell adhesion molecule (EpCAM), for rapid evaluation of surgical margins and lymph node metastasis status. Methods: The SERS biosensor was consisted of Au-IR808@EP and Beats@EP. Gold nanoparticles (AuNPs) were synthesized by sodium citrate reduction, which was then functionalized with EpCAM antibody and the Raman reporter IR808 to construct Au-IR808@EP. After physicochemical characterization, EpCAM-targeting ability of the biosensor was evaluated using EpCAM antigen standards and breast cancer cell lines. Tissue homogenates prepared from mouse models bearing high EpCAM-expressing MDA-MB-231-Epcam tumors, MCF-7 tumors, and the metastatic lymph nodes (MLNs) were then analyzed under the SERS biosensor to evaluate the pathology of tissues. Finally, clinical application was validated using surgical specimens from 20 breast cancer patients across two centers to distinguish malignant from normal tissues and identify MLNs. Results: The EpCAM-targeted SERS biosensor was successfully fabricated and formed a stable double-antibody sandwich complex upon antigen binding. It exhibited a detection limit (LOD) of 6.96 pg/mL for EpCAM standard solution. Subsequently, the method demonstrated excellent targeting capability in the detection of various breast cancer cells, with an LOD of 341 cells for MCF-7. In mouse models, the biosensor enabled rapid EpCAM detection within 11 minutes, effectively differentiating between high-EpCAM (MDA-MB-231-EpCAM) and low-EpCAM (MDA-MB-231-NC) tumors and MLNs. Meanwhile, it precisely differentiated tumor from normal tissues in 30 MCF-7 tumor-normal pairs (AUC = 1), and achieved an AUC of 0.995 in detecting 28 MLNs. Clinically, ex vivo rapid evaluation via the SERS biosensor effectively discriminated malignant breast tissues from normal tissues lesions (AUC = 0.91) and identified metastatic lymph nodes (AUC = 0.889) in surgical specimens from 20 BC patients. Conclusion: We successfully constructed an ultrasensitive SERS biosensor for efficient EpCAM targeting and rapid dual-functional assessment of surgical margins and nodal metastasis. As BCS and SNLB procedures play an increasingly important role towards precision surgery, this innovative technology holds strong potential to achieve optimized cosmetic appearances and better clinical outcomes. Citation Format: K. Lou, J. Bai, S. Fu, X. Shen, Y. Gao, S. Lin, C. Li, Y. Chen, G. Zhang. Rapid and ultrasensitive detection of surgical margin and metastatic lymph node via EpCAM-targeted surface-enhanced Raman scattering biosensor in breast cancer abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS4-05-02.