Novel Humanized Ferritin-Based NIR Fluorescent Probe for Identifying Sentinel Lymph Node Metastasis in Early Gastric Cancer

With the widespread adoption of early cancer screening, the proportion of early gastric cancer (EGC) in China has been gradually increasing. The primary treatments for EGC are endoscopic and surgical interventions. For EGC invading the submucosal layer, the lymph node metastasis rate is approximately 20%. In clinical practice, subtotal gastrectomy combined with D2 lymphadenectomy is commonly performed to achieve radical tumor resection, resulting in up to 80% of patients undergoing unnecessary lymph node dissection. Sentinel lymph nodes (SLNs), which are the first potential sites along the lymphatic drainage pathway from the primary tumor to receive cancer cells, can effectively represent the status of lymphatic metastasis. As gastric cancer surgery evolves toward minimally invasive, precise, and individualized approaches, there is an urgent clinical need for a safe and effective SLN mapping technique to intraoperatively distinguish between benign and malignant SLNs, thereby avoiding unnecessary lymphadenectomy and improving patient prognosis. Currently, indocyanine green (ICG) is the only clinically approved near-infrared (NIR) fluorescent dye and is relatively widely used. However, it lacks targeting specificity, diffuses too rapidly, and has difficulty identifying micrometastases in SLNs. Therefore, we aimed to enhance ICG's targeting ability toward metastatic tumor cells to increase fluorescence signal intensity in malignant SLNs, enabling intraoperative differentiation between benign and malignant SLNs and reducing unnecessary lymph node dissection. Considering the high heterogeneity of tumor cells and the molecular diversity among metastatic foci within malignant SLNs, our team innovatively proposed a multi-target probe design to improve targeting capability against heterogeneous tumor cells. Based on molecular imaging technology combined with near-infrared (NIR) imaging, we developed a humanized ferritin-based probe (VE/CX-FTn) targeting metastatic lymph nodes. Previous studies have confirmed the effective identification of metastatic lymph nodes by the VE/CX-FTn probe. To further validate the effectiveness of this probe in identifying SLN metastasis in early gastric cancer with a low lymph node metastasis rate, this study plans to use residual early gastric cancer tissues obtained from post-surgical resections to evaluate the probe's imaging capability for SLNs. Furthermore, a prospective clinical sample cohort study will be conducted to verify its diagnostic efficacy for metastatic lymph nodes of varying sizes. The aim is to demonstrate that our developed probe can guide the identification of SLNs in early gastric cancer and assist in determining the presence of SLN metastasis, thereby reducing unnecessary lymphadenectomy and improving patient prognosis. This study employs a novel NIR fluorescent molecular probe, VE/CX-FTn-ICG, based on humanized ferritin, with the objective of investigating its effectiveness in distinguishing between benign and malignant sentinel lymph nodes in early gastric cancer. Using this probe, we have already demonstrated that VE/CX-FTn-ICG enables precise differentiation between benign and malignant lymph nodes in animal models. The probe specifically binds to tumor cells, exhibiting high targeting specificity and imaging capability, thereby providing real-time and accurate intraoperative imaging of SLNs for early gastric cancer surgery. A further goal of this study is to validate the application efficacy of this targeted probe in distinguishing between benign and malignant SLNs using ex vivo human early gastric cancer tissue samples. This aims to provide a reliable auxiliary tool for intraoperative SLN biopsy in early gastric cancer, assisting in avoiding unnecessary lymph node resection for patients, and ultimately improving surgical outcomes and patient prognosis.