Epithelial Cell Adhesion Molecule Is an Accurate Target for Fluorescence Guided Imaging of Lymph Nodes

Purpose: Lymph node (LN) excision is critical in oncologic surgery to provide important therapeutic and diagnostic information. LN evaluation helps in staging cancers, predicting prognosis and improving survival. The ultimate wish of a surgical oncologist would be to localize and dissect all pathologically positive LNs while avoiding the morbidity of removing true negative LNs. The goal of our study was to identify a reliable marker for intraoperative molecular imaging of LNs with cancer cells from non-small cell lung cancer versus a LN without. Procedures. We identified Epithelial Cell Adhesion Molecule (EpCAM), a membrane protein normally expressed in epithelial tissues including lung. We performed immunofluorescence staining on human specimens with a conjugated anti-EpCAM monoclonal antibody. Results: Fluorescence was significantly higher in LNs with metastases as shown in 48 positive LNs from patients with resected primary lung cancer. There was high fluorescence in both hilar and mediastinal LNs, and in all primary tumor histologies. Conclusions: EpCAM may be useful for the surgical oncologist for intraoperative molecular imaging of positive LNs from lung cancer.