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Epidermal Growth Factor Receptors and Ki-67 Immunohistochemical Expression in Ameloblastoma

Dunia W Sabea

Ameloblastoma is the most frequent benign tumor of the odontogenic tumors that develops in the jaw. Nevertheless, a high rate of recurrence is reported after surgery. Epidermal growth factor receptor (EGFR) has been shown an importance in the genesis and behavior of some types of this tumor like solid multilocular ameloblastoma. Ki-67 is a molecule that can be easily detected in proliferating cells in order to gain an understanding of the rate at which the cells within a tumor are growing. The aim of this study was to examine the expression rate of EGFR and Ki-67 to clarify their role in the biological behavior of the lesions. The Oral Pathology Department of the Faculty of Dentistry in Damascus University received 25 specimens of ameloblastoma in the period October 2005 to October 2010. These specimens were studied immunohistochemically with anti EGFR and anti Ki-67 monoclonal antibodies. This study compared these with 10 normal dental buds which were taken from an aborted foetus of age 7 months in accordance with the relevant laws. Results showed that the average age of patients from which the samples were taken was 43.2 years. A tendency to affecting females was observed (72% of affected patients were females). Observed tumor types were as follows: 12 follicle type, 7 plexiform type, 6 of them were admixed. EGFR was found to be highly expressed in 19 specimens, mildly expressed in 5 specimens, and negative in only one specimen. Ki-67 expression was close to that of EGFR. There was a statistically significant relationship between the expression of the EGFR and Ki-67 monoclonal antibodies and the different patterns of the tumor islands (p<0.01). In conclusion, ameloblastoma is a positive EGFR tumor. There was a high Ki-67 index, which is associated with a high proliferation rate, which may indicate a high recurrence rate as proven by other studies