Immunolocalization of VEGF-A and orosomucoid-1 in odontogenic myxoma.

OBJECTIVE The aim of the present study was to determine and establish the immunohistochemical distribution of VEGF-A and ORM-1 protein in odontogenic myxomas to suggest a possible function in the biological behavior of odontogenic myxomas. MATERIALS AND METHODS A total of 33 odontogenic myxoma cases and three tooth germs were included. Immunohistochemistry was performed to localize VEGF-A and ORM-1 proteins in tumor cells, endothelial cells and extracellular matrix in the odontogenic myxomas. The intratumoral microvessel density (MVD) was determined with CD34 and Factor VIII antibodies. RESULTS Immunopositivity was strong in the endothelial cells, which compose various vessels, and in the randomly oriented stellate, spindle-shaped and round tumoral cells with long cytoplasmic processes. More than half of the extracellular matrix lacked expression of VEGF-A. ORM-1 expression was strong in both endothelial cells and tumor cells, and the myxoid extracellular matrix was positive, with moderate or strong immunoexpression in all cases. An important finding of this study was the statistically significant positive correlation between the expression of ORM-1 and VEGF-A in tumor cells (p=0.02). CONCLUSIONS The results of this study suggest that the expression of VEGF-A and ORM-1 may be associated with two mechanisms (angiogenesis and tumor structural viscosity) that may influence tumor growth in odontogenic myxoma.