Expression of Epidermal Growth Factor Receptor in Lymph Node Metastases of Head and Neck Squamous Cell Carcinomas

Background: An overexpression of the epidermal growth factor (EGF) receptor has been found in a wide variety of malignancies including squamous cell carcinomas of the head and neck. The overexpression of EGF receptor is of increasing interest because of a possible contribution to metastasis. Primary tumors and metastasis may differ in the expression of EGF receptor and provide a basis for metastasis. Material and Methods: This study examined the expression of the cell-surface receptor for EGF on 30 cervical lymph node metastases and on 30 primary squamous cell carcinomas of the oropharynx and the oral cavity. Immunoreactive receptor was localized using a mouse monoclonal antibody which reacts with sequences in the external domain of the receptor. Results: We saw a significant higher expression of EGF receptor in lymph node metastases than in primary tumors (p = 0.005). Examining the primary tumors, there was no correlation between the EGF receptor level and tumor localization or TNM-stage. On the other hand, we did find an interesting correlation between EGF receptor level and grading of the tumors, EGF receptor expression being significantly higher in G3 than in G1-G2 tumors (p = 0.001). Conclusions: EGF receptor system may play an important role in regulating the growth of head and neck cancer, and the process of metastasis and elevated EGF receptor level might characterize more metastatic tumors. The significant correlation between EGF receptor level and the histological grading suggests that EGF receptor expression may identify biologically more aggressive tumors.