HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology

 

Immunohistochemical expression of thymosin ß4 in ameloblastomas and odontomas

Tamotsu Kiyoshima1, Kengo Nagata1, Hiroko Wada1, Hiroaki Fujiwara1, Maho Shiotsuka1,2, Makiko Kihara1,2, Kana Hasegawa1,3, Hirotaka Someya1,4 and Hidetaka Sakai1

1Laboratory of Oral Pathology, Division of Maxillofacial Diagnostic and Surgical sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan, 2Department of Orthodontics, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan, 3Department of Endodontology and Operative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan and 4Department of Removable Prosthodonitcs, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.

Offprint requests to: Hidetaka Sakai, DDS, Ph.D., Laboratory of Oral Pathology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582 Japan. e-mail: hsakaiop@dent.kyushu-u.ac.jp


Summary. Ameloblastoma is regarded to be a benign odontogenic tumor, but it is destructive, locally invasive and presents a high rate of recurrence. Thymosin ß4 (Tß4) is closely associated with tooth germ development. Tß4 also plays a role in malignant progression and invasion. However, little is known about the function of Tß4 in odontogenic tumors. Thus, we investigated Tß4 expression in ameloblastomas and compared it with odontomas. We immunohisto-chemically evaluated the expression of Tß4, ameloblastin (AMBN), amelogenin (AMEL) and enamelin (ENAM) in 57 samples of ameloblastomas from 40 patients, and also assessed the expression of these molecules in 11 cases of odontomas, two of ameloblastic fibro-odontomas and one of tooth germ-like structures without the formation of enamel and dentin. Tß4 signals were observed in almost all of the ameloblastomas. The signals were observed in both peripheral columnar cells and central polyhedral/angular cells. Similar findings were observed in tooth germ-like structures, and in the ameloblastomatous nests in the ameloblastic fibro-odontomas. These samples had negative results for AMBN, AMEL and ENAM. Meanwhile, Tß4 signals were not seen in the odontomas, although immunolabeling for AMBN, AMEL and ENAM was observed in the enamel matrix and in some ameloblasts. Ectomesenhymal regions in the odontomas were negative for staining with the antibodies for AMBN, AMEL and ENAM. These results suggest that Tß4 could be associated with morphogenesis and tumor invasion in the ameloblastoma, and that Tß4 may play a role in the behavior of ameloblastoma
. Histol Histopathol 28, 775-786 (2013)

Key words: Thymosin ß4, Ameloblastoma, Odontoma, Tooth germ development, Odontogenic tumor

DOI: 10.14670/HH-28.775