Epithelial growth factor receptor (EGFR) expression in squamous cell cancer of buccal mucosa: Incidence and correlation with tumor characteristics in Indian population.

Abstract

e16021 Background: A key motivation for investigating head and neck cancer in India is to understand molecular pathways in carcinogenesis and find indicators of patient survival or markers to select the type of treatment. Methods: We evaluated 50 cases attending our center with squamous cell carcinoma of buccal mucosa (SCCBM) to document the incidence of EGFR over expression of primary tumor; establish a correlation between EGFR over expression by Immunohistochemistry (IHC) and tumor characteristics. Also compare EGFR expression by IHC with the EGFR by FISH. After the Hospital IRB approval, IHC staining for EGFR was performed on the FFPE block of tumor tissue.IHC staining of tissue samples was performed using the Anti EGFR Polyclonal, Biogenex, USA. The tumor tissue was sent to reference laboratory for EGFR analysis by FISH Test code 19041Xa. Data collected was analyzed using SPSS 11.0 for Windows. Results: A total of 50 patients were studied from December 08 to June 10. Mean age was 50.24 years (86% males & 14% females). Tobacco chewing reported by 52%, Betel nut chewing 2% and multiple habits in 34%. Sub mucous fibrosis was noted in 30%, leukoplakia in 8%. Premalignant lesions were associated with higher EGFR expression. No statistical difference was noted in pattern of EGFR expression as per the tumor size, nodal status, stage, grade, cut margin status, LVI and PNI. EGFR over expression by IHC was seen in 62% patients, while FISH revealed EGFR amplification in only 22% of tissue samples. EGFR positive by IHC had a sensitivity of 81.82% & specificity of 38.24%. A statistically significant increase in EGFR over expression (both 2+ and 3 +) with increase in depth of invasion of tumour was noted (p value 0.044). Conclusions: The study demonstrates EGFR over expression (by IHC) in 62% patients with SCCBM in Indian population. Significant EGFR over expression by IHC was noted in tumors with pre malignant lesions. Increasing EGFR expression was noted with increasing depth of tumor.