S115 The Receptor Tyrosine Kinase c-MET Is Mutated in Head and Neck Cancer and Is a Promising Novel Target

Abstract

Background: During ablative head and neck cancer procedures, a surgeon’s assessment of tumor extent is dependent on subtle tissue changes and palpation. Accurate assessment of tumor extent by fluorescent optical imaging has the potential to provide surgeons real-time, intraoperative information about the local extent of tumor and the presence of residual disease. Design: Orthotopically inoculated head and neck squamous cell carcinoma cells UM-SCC-1 (n=6), CAL 27 (n=6), or saline-injected controls were monitored for 14 days and then underwent mock surgical resections. Antiepidermal growth factor receptor antibody (cetuximab) was labeled with a near-infrared fluorochrome, Cy5.5. The cetuximab-Cy5.5 conjugate was systemically administered by tail vein injection 3 days prior to the resection. Near-infrared fluorescent monitoring was performed before resection and after partial and complete surgical excision of the tumors. After resection, the mandible and attached soft tissues were resected, paraffin embedded, and serial sectioned. Results: After transcervical serial tumor resections, near-infrared stereomicroscopy was used to detect residual disease attached to the soft tissues or mandible in both cell lines. Histological analysis of serial sections of the mandible and floor of mouth after resection demonstrated that in every case negative fluorescence corresponded to the absence of residual tumor. The smallest residual disease that could be detected (SCC-1 cell line) was 0.7 mm. The location of residual disease visualized by fluorescence stereomicroscopy was confirmed on histological sections. Conclusion: Near-infrared stereomicroscopy after systemic administration of cetuximab labeled with Cy5.5 may enable surgeons to visualize residual disease intraoperatively. S115 The Receptor Tyrosine Kinase c-MET Is Mutated in Head and Neck Cancer and Is a Promising Novel Target