Open-field fluorescence guided imaging of ameloblastoma tumors in mouse patient-derived xenograft model

PURPOSE: The aim of our study is to use near infrared fluorescence imaging to demonstrate the localization of cetuximab-IRDye800 to ameloblastoma in vivo. METHODS: Ameloblastoma tumor tissue from three patients was implanted subcutaneously into athymic nude mice to form patient-derived xenografts (PDX). Animals were randomly divided into two groups; one received the epidermal growth factor receptor (EGFR) antibody, cetuximab-IRDye800, and the other received the control antibody, IgG-IRDye800. After resection of the overlying skin, the tumors were imaged on the LUNA device, an open-field, intraoperative device. Tumor/background ratios (TBRs) were calculated and statistically analyzed using a paired t test. RESULTS: Imaging of PDX tumors revealed the TBRs produced by cetuximab-IRDye800 (AB-20, 4.5 ± 1.57; AB-33, 1.17 ± 0.42; AB-34, 1.33 ± 0.04) were significantly higher than those produced by IgG-IRDye800 (AB-20, 2.02 ± 0.29; AB-33, 1.07 ± 0.30; AB-34, 1.11 ± 0.13; p values, AB-20, p < 0.021; AB-33; p < 0.045; AB-34; p < 0.017). Excised PDX tissues were paraffin-embedded to confirm the presence of tumor by H&E staining and EGFR expression. CONCLUSION: Fluorescently labeled anti-EGFR demonstrates specificity and sensitivity for PDX tumor xenografts using an open-field, near-infrared imaging system. These open-field devices allow real-time clinical assessment of fluorescent signals during surgery and may provide future benefit in the removal of ameloblastoma tumors.