Stromal expression of CD90 in our POT cases was found in blood vessels and in some mesenchymal cells, particularly in those in close proximity to epithelial odontogenic cells, which led us to suggest that CD90 expression in POT could play an important role in cellular adhesion and migration, serving as an important regulator of cell-matrix interactions for determining the biological behavior of this tumor. This evidence concerns the gene THY1 and neoplasm.