ORIGINAL ARTICLE Isolation and characterization of stem cells derived from human third molar tooth germs of young adults: implications in neo-vascularization, osteo-, adipo- and neurogenesis ME Yalvac 1,7 , M Ramazanoglu 2,7 , AA Rizvanov 1,3,4 , F Sahin 1 , OF Bayrak 1 , U Salli 5 , A Palota ´s 6 and GT Kose 1 1 Department of Genetics and BioEngineering, College of Engineering and Architecture, Yeditepe University, Kayisdagi, Istanbul, Turkey; 2 Department of Oral Surgery, College of Dentistry, Istanbul University, Capa, Istanbul, Turkey; 3 Department of Genetics, Faculty of Biology and Soil Sciences, Kazan State University, Kazan, Russia; 4 Core Research Laboratory, Kazan State Medical University, Kazan, Russia; 5 Department of Pharmacology, College of Medicine, Pennsylvania State University, Hershey, PA, USA and 6 Asklepios-Med Bt. (Private Practice and Research Center), Szeged, Hungary Correspondence: AA Rizvanov, Department of Genetics, Faculty of Biology and Soil Sciences, Kazan State University, ul. Kremlevskaya 18, R-420008 Kazan, Russia. or Dr A Palota ´s, Asklepios-Med Bt, H-6722 Szeged, Kossuth Lajos sgt. 23, Szeged H-6722, Hungary. E-mail: rizvanov@gmail.com or palotas@asklepios-med.eu 7 These authors contributed equally to this work. Received 21 April 2009; revised 9 July 2009; accepted 27 July 2000 A number of studies have reported in the last decade that human tooth germs contain multipotent cells that give rise to dental and peri-odontal structures. The dental pulp, third molars in particular, have been shown to be a significant stem cell source. In this study, we isolated and characterized human tooth germ stem cells (hTGSCs) from third molars and assessed the expression of developmentally important transcription factors, such as oct4, sox2, klf4, nanog and c-myc, to determine their pluri-potency. Flow- cytometry analysis revealed that hTGSCs were positive for CD73, CD90, CD105 and CD166, but negative for CD34, CD45 and CD133, suggesting that these cells are mesenchymal-like stem cells. Under specific culture conditions, hTGSCs differentiated into osteogenic, adipogenic and neuro- genic cells, as well as formed tube-like structures in Matrigel assay. hTGSCs showed significant levels of expression of sox2 and c-myc messenger RNA (mRNA), and a very high level of expression of klf4 mRNA when compared with human embryonic stem cells. This study reports for the first time that hTGSCs express developmentally important transcription factors that could render hTGSCs an attractive candidate for future somatic cell re-program- ming studies to differentiate germs into various tissue types, such as neurons and vascular structures. In addition, these multipotential hTGSCs could be important stem cell sources for autologous transplantation. The Pharmacogenomics Journal advance online publication, 1 September 2009; doi:10.1038/tpj.2009.40 Keywords: germ; molar; stem cell; tooth; transcription factor Introduction Besides presenting an important potential for developing stem cell-based therapies, adult stem cells present less ethical controversy compared with embryonic stem cells (ESCs). The mesenchymal stem cell, primarily obtained from bone marrow stroma, is one of the most promising adult stem cell types for regenerative medicine. 1,2 Bone marrow-derived mesenchymal stem cells have been shown to differentiate into various cell types. 3–7 However, for various reasons, such as surgical trauma caused by bone marrow isolation procedures or bone marrow-related diseases, much of the stem cell research has focused on finding alternative resources of adult stem cells that require non-invasive or The Pharmacogenomics Journal (2009), 1–9 & 2009 Nature Publishing Group All rights reserved 1470-269X/09 $32.00 www.nature.com/tpj