Evaluation of epidermal growth factor receptor gene and chromosome 7 alterations in squamous cell carcinoma of the larynx, using chromogenic in situ hybridization on tissue microarrays

Abstract

Aims: To identify subgroups of patients with squamous cell carcinoma (SCC) of the larynx, characterized by the specific deregulation mechanism of the epidermal growth factor receptor (EGFR) gene, and to evaluate EGFR protein expression levels and correlate these with biological and clinicopathological parameters.Materials and methods: Using tissue microarray technology, 50 formalin-fixed, paraffin-embedded primary laryngeal SCCs were cored and re-embedded into one block. Immunohistochemistry and chromogenic in situ hybridization were performed.Results: Epidermal growth factor receptor protein over-expression was observed in 27/50 (54 per cent) cases and was statistically associated with tumour grade (p=0.028). Epidermal growth factor receptor gene alterations were identified in 5/50 (10 per cent) cases, which demonstrated amplification (n=4) and deletion (n=1). Chromosome 7 instability was detected in 8/50 (16 per cent) cases.Conclusions: Epidermal growth factor receptor over-expression is a frequent event in SCCs, but it does not predict a specific molecular mechanism of gene deregulation for targeted therapeutic strategies via monoclonal antibodies.