The survival rate of esophageal squamous carcinoma (ESCC) after surgical resection is estimated to be only 30.3% due to the difficulty in identifying microinfiltration and subtle metastases. In this study, we explored the value of near-infrared fluorescence in the second window (NIR-II) using an epidermal growth factor receptor (EGFR)-targeted probe (cetuximab-IR800) for the intraoperative navigation of ESCC in xenograft mouse models. Immunohistochemical results showed that EGFR was aberrantly expressed in 94.49% (120/127) of ESCC tissues and 90.63% (58/64) of metastatic lymph nodes. Western blot results demonstrated that EGFR protein was highly expressed in ESCC cell lines. Flow cytometry data revealed that cetuximab-IR800 showed a stronger binding specificity in EGFR-positive KYSE-30 cells than in A2780 control cells (P < 0.01). In vivo imaging data showed that the ratio of mean fluorescent intensity (MFI) and tumor to background (TBR) was significantly higher in KYSE-30 subcutaneous tumors with the infusion of cetuximab-IR800 than in those with the infusion of IgG1-IR800 (P < 0.05). Surgical navigation with NIR-II imaging showed that the TBR in orthotopic ESCC was significantly higher than that of NIR in the first window (NIR-I) (2.11 ± 0.46 vs 1.58 ± 0.31, P < 0.05), and NIR-II was more sensitive than NIR-I in detecting subcentimeter metastases (94.87% (37/39) vs 58.97% (23/39), P < 0.001). In conclusion, cetuximab-IR800 with high specificity for ESCC was first used in NIR-II surgical navigation. This probe showed better imaging resolution and higher sensitivity in detecting subtle metastases derived from an orthotopic ESCC model than NIR-I, which indicates that NIR-II has promise in guiding precise surgery for ESCC patients.
Keywords: epidermal growth factor receptor; esophageal squamous cell carcinoma; molecular imaging; near-infrared II window fluorescence; surgical navigation.