IMMUNOHISTOCHEMICAL INVESTIGATION OF EPIDERMAL GROWTH-FACTOR RECEPTOREXPRESSION IN AMELOBLASTOMAS

Immunohistochemical analysis was performed to determine the localizati on of epidermal growth factor receptor (EGFR) in ameloblastomas. Amelo blastoma samples were classified into follicular, plexiform, and basal cell types. The number of cases in each category was 17, 19 and 3, re spectively. Ameloblastomas, disregarding their histological type, cons ist of two cell forms: peripheral columnar cells and central stellate cells. The frequency of EGFR expression was much higher in the latter than in the former (P<0.005). On analysis with respect to histological types, the frequency of EGFR expression in columnar cells was not sig nificantly different between the follicular and the plexiform types, b ut was observed more frequently in the stellate cells in the follicula r than in the plexiform ameloblastomas (P<0.05). This pattern of EGFR expression was not consistent with the PCNA staining pattern, but was similar to that of keratin expression which we have reported previousl y. The present study suggests that EGFR expression in ameloblastomas i s closely associated with tumour differentiation, and squamous differe ntiation in particular.