Immunohistochemical detection of phosphorylated Akt, PI3K, and PTEN in ameloblastic tumors.
OBJECTIVE
To evaluate roles of the Akt signaling pathway in oncogenesis and cytodifferentiation of odontogenic tumors, expression of phosphorylated Akt (pAkt), PI3K, and PTEN was analyzed in ameloblastic tumors as well as in tooth germs.


METHODS
11 tooth germs, 40 ameloblastomas, and 5 malignant ameloblastic tumors were examined immunohistochemically with antibodies against pAkt, PI3K, and PTEN.


RESULTS
Immunoreactivity for pAkt, PI3K, and PTEN was detected predominantly in odontogenic epithelial cells near the basement membrane in tooth germs and ameloblastic tumors. The levels of immunoreactivity for pAkt and PI3K were slightly higher in ameloblastic tumors than in tooth germs. Plexiform ameloblastomas showed significantly higher expression of PI3K than follicular ameloblastomas, and PI3K immunoreactivity in ameloblastomas without cellular variation was significantly higher than that in acanthomatous ameloblastomas. The level of PTEN immunoreactivity was significantly lower in ameloblastomas than in tooth germs.


CONCLUSIONS
Expression of pAkt, PI3K, and PTEN in tooth germs and ameloblastic tumors suggests that these signaling molecules regulate cell survival and growth in normal and neoplastic odontogenic tissues by mediating growth factor signals. Increased expression of pAkt and PI3K and decreased expression of PTEN in ameloblastic tumors may participate in oncogenesis of odontogenic epithelium by activating the Akt signaling pathway.
Kumamoto
Hiroyuki
H
Division of Oral Pathology, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Japan. kumamoto@mail.tains.tohoku.ac.jp
Ooya
Kiyoshi
K
D000564:Ameloblastoma / Q000737:chemistry* / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D007573:Jaw Neoplasms / Q000737:chemistry* / Q000601:surgery; D008565:Membrane Proteins / Q000032:analysis*; D051058:Oncogene Protein v-akt / Q000032:analysis*; D051059:PTEN Phosphohydrolase / Q000032:analysis*; D018709:Statistics, Nonparametric
D008565:Membrane Proteins; D051058:Oncogene Protein v-akt; C446603:TPTE protein, human; D051059:PTEN Phosphohydrolase