Expression of SOX2 and EGFR in Ameloblastoma, Odontoameloblastoma and Ameloblastic Carcinoma

Abstract

Introduction: While de novo Ameloblastic Carcinomas (ACs) are easily diagnosed, it is the benign Ameloblastoma (AM) showing areas of malignant transformation which is a diagnostic challenge. SOX2, a transcription factor and Epidermal Growth Factor Receptor (EGFR) are oncogene on virtue of being embryogenic including odontogenic and adult stem cell regulator. Both are aberrantly expressed and amplified in several epithelial human cancers and have been used as immunohistochemical markers. Aim: To determine the expression of SOX2 and EGFR in AM, Odontoameloblastoma (OA) and AC in order to assess efficacy of the markers in differentiating between these tumours. Materials and Methods: This retrospective study was conducted to determine the immunohistochemical expression of SOX2 and EGFR on microscopic sections of AM (n=11), OA (n=2) and AC (n=6) retrieved from archives of the Department of Oral Pathology, Vydehi Institute of Dental Sciences, Bengaluru, India, from the period of January 2010 to December 2015. The data obtained were analysed using statistical software IBM SPSS version 21.0. Results: EGFR expression was noted in all cases of AM, OA and AC. Eight cases (72.72%) of AM showed SOX2 negative expression. Five cases (83%) of AC showed SOX2 positive expression (p≥0.05). Both the cases of OA demonstrated SOX2 positivity. Two cases (50%) of recurrent AMs (n=4) showed SOX2 overexpression. Conclusion: While SOX2 has negative expression in AM, its positivity in OA and AC reiterates, its role in presence of cell lineage of tooth development and as an adjunct marker to highlight suspicious tumour aggregates respectively. SOX2 overexpression in recurrent cases of AM can be used to followup the patient. Strong EGFR overexpression indicates possibility of anti-EGFR treatment modality for both AM and AC.

Keywords

• biomarkers
• immunostaining
• odontogenic carcinoma
• odontogenic tumour
• oncogene