Expression of p63 and p73 in ameloblastomas.
BACKGROUND
To clarify the role of p53 homologs in oncogenesis and cytodifferentiation of odontogenic tumors, expression of p63 and p73 was analyzed in ameloblastomas as well as tooth germs.


METHODS
Tissue specimens of nine tooth germs and 48 benign and five malignant ameloblastomas were examined by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) for the expression of p63 and p73.


RESULTS
Immunoreactivity for p63 and p73 was evident in epithelial cells neighboring the basement membrane in developing and neoplastic odontogenic tissues. p63 expression in desmoplastic ameloblastomas was significantly higher than in acanthomatous and granular cell ameloblastomas, and ameloblastic carcinomas showed higher p63 expression than metastasizing ameloblastomas. p73 expression was significantly higher in plexiform ameloblastomas than in follicular ameloblastomas, and basal cell ameloblastomas showed higher p73 expression than granular cell ameloblastomas. mRNA transcripts for Delta Np63 and TAp73 were detected in all developing and neoplastic odontogenic tissues. TAp63 mRNA was expressed in five of eight tooth germs, 16 of 34 ameloblastomas, and one of one malignant ameloblastoma, whereas Delta Np73 mRNA was recognized in one of eight tooth germs, nine of 34 ameloblastomas, and one of one malignant ameloblastoma.


CONCLUSIONS
The expression of p63 and p73 suggests that these p53 homologs play a role in differentiation and proliferation of odontogenic epithelial cells. Variations of predominantly expressed isoforms suggest that p63 and p73 might differentially function in odontogenic tissues.
Kumamoto
Hiroyuki
H
Division of Oral Pathology, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai 980-8575, Japan. kumamoto@mail.tains.tohoku.ac.jp
Ohki
Kousuke
K
Ooya
Kiyoshi
K
D000564:Ameloblastoma / Q000145:classification / Q000235:genetics* / Q000556:secondary; D017209:Apoptosis / Q000235:genetics*; D001485:Basement Membrane / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics*; D004847:Epithelial Cells / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D016147:Genes, Tumor Suppressor; D006801:Humans; D007150:Immunohistochemistry; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics*; D010750:Phosphoproteins / Q000032:analysis / Q000235:genetics*; D020033:Protein Isoforms / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014083:Tooth Germ / Q000378:metabolism; D015534:Trans-Activators / Q000032:analysis / Q000235:genetics*; D014157:Transcription Factors; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000235:genetics*
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D020033:Protein Isoforms; C115051:TP63 protein, human; C000606460:TP73 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C000606369:delta Np73 protein, human