An Immunohistochemical Study of Cell Adhesion Molecule Expression and Cell Proliferative Activity in Ameloblastomas:With a Special Reference to the Morphological Difference in Follicular and Plexiform Patterns

Abstract

Ameloblastomas originate from the odontogenic epithelium and are known as odontogenic tumors. Histopathologically, they are classified as follicular and plexiform patterns. However, there have been few reports concerning the morphological difference between these patterns. Cell adhesion and proliferation play important roles in maintaining tissues as well as in organ genesis and morphogenesis. To clarify the association of cell adhesion molecules and cell proliferation in the morphological difference between follicular and plexiform patterns of ameloblastomas, the expressions of E- and P-cadherins, alpha- and beta-catenins, integrin alpha3-betal (VLA-3) and proliferative cell nuclear antigen (PCNA) were examined by immunohistochemical analyses in 35 ameloblastomas. In the follicular pattern, the columnar and spindle cells showed 43.8% PCNA-positively. Those of the plexiform pattern showed 42.1 %. The stellate reticulum-like cells (SRLC) of the follicular demonstrated 24.5% positively. The cells of the plexiform pattern showed 32.8% positively. PCNA-positive rate differed significantly between the patterns for SRLC. E-cadherin, P-cadherin, and VLA-3 were expressed in all parenchyma cells in the plexiform pattern. In the follicular pattern, the columnar and spindle cells expressed these adhesion molecules, but levels were decreased in SRLC. Alpha- and beta-catenins were seen in all parenchyma cells of both patterns of ameloblastomas. These findings support that SRLC of the plexiform pattern had greater adhesive ability than those of the follicular one. The degree of cell differentiation might differ between the follicular and plexiform patterns. These results suggested that the cell adhesion molecules and cell-proliferating activity mediated the morphological difference in ameloblastomas.