Immunohistochemical detection of erythropoietin, platelet-derived growth factor and their receptors in ameloblastomas

Ameloblastoma (AB) is the most common odontogenic epithelium-derived tumor, but has unclear etiology. Various ligand/receptor systems are implicated in ameloblastoma development. In this study, we explored the expression of erythropoietin (EPO), platelet-derived growth factor (PDGF) and their receptors (EPOR, PDGFR) in ABs, and the potential origins of ABs from keratocystic odontogenic tumors (KCOTs) and tooth germs in control groups. Immunostaining was performed using antibodies for EPO, EPOR, PDGF-A and PDGFR-ct. Statistical analysis was performed based on immunoreactivity. We found that EPOR expression was significantly higher in ABs than in KCOTs (P<0.05), but was similar to that of tooth germs. EPOR expression was also significantly different between the AB subtypes (P<0.05). Nevertheless, EPO expression was only significantly different between tooth germs and KCOTs (P<0.05). Immunoreactivity for PDGFR-α and PDGF-A was stronger in ABs than in KCOTs and tooth germs. However, significant differences were only found between individual groups or among types or subtypes of ABs (P<0.05 or P<0.01). In addition, the expression of both EPOR and PDGFR-α in the recrudescent ABs was significantly greater than in primary ABs (P<0.01). We conclude that EPO, EPOR, PDGF-A and PDGFR-α are essential for the growth of human teeth as well as for oncogenesis, development, cell differentiation and biological behavior of odontogenic neoplasm.