Immunohistochemical evaluation of EGFR expression in lip squamous cell carcinoma. Correlation with clinicopathological characteristics

Abstract

Background: The majority of lip cancer is the squamous cell carcinoma (SCC) type that exhibits clinical and biological characteristics intermediate between skin and oral SCC. The aim of this study was to assess the impact of epidermal growth factor receptor (EGFR) expression on prognosis of lip squamous cell carcinoma (LSCC) and to relate it with clinicopathological features. The role of EGFR expression as a possible therapeutic target was also discussed. Methods: A series of 55 patients with LSCC was analyzed. EGFR expression was determined by standardized immunohistochemistry (pharmDx assay) and evaluated by both manual and automated image analysis (ACIS III). The Kappa statistic test was used to evaluate the concordance of manual and automated scores. EGFR results were correlated with clinicopathologic characteristics. Statistical differences between proportions were determined by the chi-squared test (with linear-by-linear correction where appropriate). The Mann-Whitney and the Kruskal-Wallis test were employed for comparison of continuous variables. Results: Correlation between manual and automated score was obtained in 50/55 cases (90.9%). EGFR expression was absent or weak in 14 cases (25.5%); borderline (2+) in 20 cases (36.4%) and positive (3+) in 21 cases (38.2%). Significant relationships were found between EGFR expression and tumour ulceration (p=0.022) and tumour thickness (p=0,002) and width (p=0.021). Conclusions: Our results revealed EGFR high expression in LSCC and its relationship with bad prognosis criteria (tumour size and ulceration).