Detection of CD133, Bmi-1, and ABCG2 in ameloblastic tumors.
BACKGROUND
To investigate the roles of stem cell-related molecules in oncogenesis and cytodifferentiation of odontogenic tumors, expression of CD133, Bmi-1, and ATP-binding cassette subfamily G member 2 (ABCG2) was analyzed in ameloblastic tumors as well as in tooth germs.


METHODS
Tissue specimens of 12 tooth germs, 47 ameloblastomas, and six malignant ameloblastic tumors were examined using reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry to determine the expression of CD133, Bmi-1, and ABCG2.


RESULTS
mRNA expression of CD133, Bmi-1, and ABCG2 was detected in all samples of normal and neoplastic odontogenic tissues. Immunohistochemical reactivity for CD133 and Bmi-1 was evident in odontogenic epithelial cells neighboring the basement membrane in tooth germs, ameloblastomas, and metastasizing ameloblastomas, and ameloblastic carcinomas and clear cell odontogenic carcinomas showed reactivity for CD133 and Bmi-1 in most neoplastic cells. The level of CD133 immunoreactivity in malignant ameloblastic tumors was significantly higher than the levels in tooth germs and ameloblastomas. Immunoreactivity for ABCG2 in odontogenic epithelial components was detected in some ameloblastic tumors but not in tooth germ tissues. Some granular neoplastic cells in granular cell ameloblastomas showed ABCG2 expression. The level of ABCG2 immunoreactivity in malignant ameloblastic tumors was significantly higher than that in tooth germs.


CONCLUSIONS
Expression of CD133, Bmi-1, and ABCG2 in tooth germs and ameloblastic tumors suggests that stem cell-related molecules might control the maintenance of odontogenic tissues. Expression of these molecules is possibly involved in oncogenesis, cell differentiation, and malignant potential of odontogenic epithelium.
Kumamoto
Hiroyuki
H
Division of Oral Pathology, Tohoku University Graduate School of Dentistry, Sendai, Japan. kumamoto@m.tains.tohoku.ac.jp
Ohki
Kousuke
K
D000071916:AC133 Antigen; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000032:analysis*; D000564:Ameloblastoma / Q000473:pathology*; D015703:Antigens, CD / Q000032:analysis*; D001485:Basement Membrane / Q000473:pathology; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000648:ultrastructure; D018432:Drug Resistance, Multiple; D004658:Enamel Organ / Q000473:pathology; D042783:Endothelial Cells / Q000473:pathology; D004847:Epithelial Cells / Q000473:pathology; D005347:Fibroblasts / Q000473:pathology; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D009363:Neoplasm Proteins / Q000032:analysis*; D009687:Nuclear Proteins / Q000032:analysis*; D009808:Odontogenic Tumors / Q000473:pathology; D010455:Peptides / Q000032:analysis*; D063150:Polycomb Repressive Complex 1; D011518:Proto-Oncogene Proteins / Q000032:analysis*; D012097:Repressor Proteins / Q000032:analysis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000473:pathology; D014083:Tooth Germ / Q000473:pathology; D016335:Zinc Fingers
C116614:ABCG2 protein, human; D000071916:AC133 Antigen; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D015703:Antigens, CD; C069077:BMI1 protein, human; D006023:Glycoproteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C000606023:PROM1 protein, human; D010455:Peptides; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1