목적: Human palatine tonsils have emerged as a new potential tissue source of multipotent mesenchymal stem cells (MSCs). It has been suggested that Fibroblast growth factor (FGF) play an important role in cell proliferation and differentiation in various MSCs. We investigated the proliferation and differentiation capacity of tonsil-derived MSC (TMSC) which have the potential to be an important source of MSCs, and the role of FGF5, a subtype of FGF, in the function of TMSCs. 방법:Palatine tonsils were obtained after informed consent from patients and their parents undergoing tonsillectomy as a result of chronic tonsillitis. For isolating stem cell, tonsil was washed extensively with equal volumes of phosphate-buffered saline (PBS), and tissue were digested at 37 °C for 30 minutes with 0.075 % collagenase (type I; Sigma, St. Louis, MO, USA). Cell proliferation was evaluated by a MTT assay, cell cycle assays and Immunofluorescent staining. Osteogenic differentiation activity of TMSC was determined using mineralization activity. 결과:In cell cycle analysis, adipose tissue-derived MSCs (ADSCs) had S and G2/M phase proportion of 17.09%, whereas TMSCs had that of 28.23%, indicating higher rate of cell proliferation. The expression of endogenous FGF5 was significantly higher in TMSCs compared to ADSCs, which has a much higher proliferation capacity. Oteogenic differentiation activity of TMSCs were relatively lower than that of ADSCs. However, the activity reduced with siFGF5 transfection, which then recovered to near normal levels when rhFGF5 was added, suggesting that FGF5 is also involved in the osteogenic differentiation of TMSCs (p<0.001). We also found that blocking FGF5 using siFGF5 led to inactivation of ERK 1/2. 결론:This study demonstrated that TMSCs have significantly higher proliferation potential compared to ADSCs. We also speculate that FGF5s regular the proliferation and osteogenic differentiation of TMSCs through the ERK 1/2 pathway.