Immunohistochemical analysis of cell proliferation and suppression of ameloblastoma with special reference to plexiform and follicular ameloblastoma

To understand proliferation and suppression in ameloblastoma that exhibit locally invasive growth and recur clinically, the expression of proliferating cell nuclear antigen (PCNA), Ki-67 antigen, topoisomerase 11 alpha, p53 and p21 proteins were analyzed with immunohistochemistry. Sections of archival ameloblastoma tissues were used (16 plexiform and 14 follicular types). Each antigen was labeled by the polymer method with optimal antigen retrieval. The plexiform type exhibited higher expression of PCNA, Ki-67 and topoisomerase 11 alpha antigens than the follicular type. Expression of PCNA correlated significantly with that of the Ki-67 antigen. The plexiform type also exhibited greater expression of p53 and p21 proteins than the follicular type. Expression of p53 protein correlated significantly with that of p21, PCNA, Ki-67 antigen and topoisomerase 11 alpha. Expression of p21 protein did not correlate with that of the proliferation-related antigens. These findings suggest that the plexiform ameloblastoma has higher proliferating activity and malignant potentiality as neoplastic cells than the follicular ameloblastoma.