Abstract 5786: Rapidly assess sentinel lymph node metastasis status in breast cancer by a near-infrared fluorescent probe targeting CK

Abstract Purpose: At present, surgery is still a main treatment method for breast malignant tumors, but the problems of edema and tumor recurrence faced by patients after surgeries are still relatively common. The main reason for this is closely related to the resection of metastatic sentinel lymph node (SLN) during surgery. The method of identifying SLN by methylene blue (MB) and technetium 99m tracing is not clearly targeted and can’t judge the metastatic status of SLNs. Therefore, there is an urgent need to develop tracers that specifically identify the metastatic status of SLN. Our team successfully synthesized ICG-CK, a fluorescent molecular probe targeting pan-CK. Through animal experiments, we found that the probe can identify the metastatic status of SLN in vivo and ex vivo. Methods: 1. The penetration and characteristics of the ICG-CK were evaluated. 2. The ability of ICG-CK to recognize different breast cancer cell lines was verified by cell uptake experiments. 3. The ability of ICG-CK to identify the metastatic status of SLN was verified by in vivo imaging experiments. 4. The ability of ICG-CK to identify the metastatic status of ex vivo SLN was verified by co-incubation with ex vivo tissue. Results: 1. The ICG-CK probe was successfully synthesized, with good stability, biocompatibility and strong NIR-II fluorescence emission ability. 2. ICG-CK could specifically target 4T1 cell which with high CK expression compared with ICG-IgG, and there was a statistically significant difference between the two, p<0.0001. 3. In vivo imaging experiments, the fluorescence imaging of tumor-bearing mice showed that ICG-CK was easily drained to SLN and targeted to identify metastatic 4T1 tumor cells, producing a strong fluorescent signal, and the SBR of metastatic SLN and normal SLN was 3.34, p<0.05. 4. By imaging isolated SLN from tumor-bearing mice, we found that after co-incubation with ICG-CK of isolated SLN, isolated SLN produced a strong fluorescent signal that was significantly different from normal SLN, p<0.01. Summary: Our results show that ICG-CK has a strong ability to identify metastatic SLN compared with normal SLN in breast cancer, both in vivo and ex vivo imaging experiments, and it can produce a strong fluorescence signal in the near-infrared second region. Therefore, our study provides a basis for further exploration of the use of ICG-CK to assess the metastatic status of SLN in real-time intraoperatively. Citation Format: Junhong Chen, Wei-Ling Chen, Yuan-Yuan Zhu Zhu, Zhao Wu, Ting-wen Guo, Guo-Jun Zhang. Rapidly assess sentinel lymph node metastasis status in breast cancer by a near-infrared fluorescent probe targeting CK [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5786.