Epidermal growth factor receptor: a novel biomarker for aggressive head and neck cutaneous squamous cell carcinoma

Abstract

There is currently no prognostic tool that reliably predicts the risk of metastasis in cutaneous squamous cell carcinoma, most of which occur in the head and neck region. Epidermal growth factor receptor has received much interest in recent years with the advent of epidermal growth factor receptor-targeted molecular therapy in clinical oncology. We investigate the role of epidermal growth factor receptor as a biomarker for head and neck cutaneous squamous cell carcinoma. Using immunohistochemistry and fluorescence in situ hybridization, we assessed the epidermal growth factor receptor protein expression and gene copy in 3 groups of head and neck cutaneous squamous cell carcinoma: primary lesions not associated with metastasis (P), primary lesions associated with subsequent metastasis (PM), and metastatic nodal disease (M). Epidermal growth factor receptor overexpression was detected in 36% and 79% of P and PM cases, respectively. Epidermal growth factor receptor overexpression was significantly associated with PM (P = .03) and was found to be an independent prognostic factor for metastasis on multivariate analysis (P = .05). However, epidermal growth factor receptor overexpression was only maintained in 47% of cases in the M group. None of the 27 cases that overexpressed the epidermal growth factor receptor protein showed gene amplification: the results were uninterpretable in 2, and polysomy and balanced disomy were detected in 5 and 20 cases, respectively. These observations may have important prognostic and therapeutic implications for head and neck cutaneous squamous cell carcinoma.