Amplification and overexpression of epidermal growth factor receptor gene in human oropharyngeal cancer

The presence of epidermal growth factor receptor (EGF-R) gene was determined in 84 patients with squamous cell carcinoma (SCC) of the oropharyngeal region--a highly prevalent, chewing-tobacco associated malignancy in India, using Southern hybridisation analysis of DNA extracted from primary tumor tissues. We observed a 3- to 8-fold amplification of EGF-R gene in 19/66 (29%) of the SCCs of the oral cavity, and about 30-fold EGF-R amplification in 2/18 (11%) hypopharyngeal cancers. Dot blot analysis of total RNA from several tumour tissues, revealed overexpression of the EGF-R gene in the examined patients, with the EGF-R gene amplified. 4 patients with single copy EGF-R gene, did not exhibit overexpression of the gene. Within our sample set, no correlation was evident between EGF-R gene amplification and clinico-pathological parameters of the malignancy. The amplification and overexpression of the EGF-R gene observed in the primary tumour tissues of 25% (21/84) of the human oropharyngeal cancers, indicate possible involvement of the gene in the pathogenesis of these cancers.