The cytobiological differences between two odontogenic cyst-lining keratinocytes.

PURPOSE Odontogenic cysts are classified into a developmental group, including follicular cysts (FC) and keratocysts, and an inflammatory group including radicular cysts (RC). In clinical cases, we frequently encounter RC and FC. The purpose of this study was to investigate the cytobiological differences between two odontogenic cyst-lining keratinocytes using a cytobiological approach from the aspect of metabolic function and the degree of maturation of the epithelium. MATERIALS AND METHODS Samples of odontogenic cyst-lining keratinocytes and oral keratinocytes collected at surgery, and of cultured oral keratinocytes, were analyzed (1) by immunohistochemical staining of granulocyte macrophage colony stimulating factor (GM-CSF), human beta defensin-2 (HBD-2) and chemokine receptor 6 (CCR6) expressing cell (Langerhans cell, helper T cell and suppressor T cell) antibodies, (2) by reverse transcription-polymerase chain reaction (RT-PCR) to determine the expression of GM-CSF and HBD-2 mRNA and (3) by gas chromatography to evaluate the composition of fatty acids (16:0, 18:2, 20:4) in the cell membranes of the keratinocytes. RESULTS 1. Immunohistochemical staining indicated that HBD-2 and GM-CSF expression were higher in RC than in FC. 2. The same results were obtained from the RT-PCR analysis. 3. The % composition of palmitic acid (16:0) was significantly higher in the RC-lining keratinocytes (38.62±5.86%) and in the FC-lining keratinocytes (30.37±1.38%) than in the normal gingiva (23.00±1.40%). The % composition of essential fatty acids (18:2+20:4) was significantly higher in the FC-lining keratinocytes (26.20±3.55%) than in the RC-lining keratinocytes (20.50±8.17%). CONCLUSION The present study demonstrated definite cytobiological evidence of the differences between RC and FC.