Objective:To compare the proportion of stem like cells from serum-supplemented medium(SSM) culture with those from serum-free medium(SFM) culture in order to obtain better methods for enriching tumor stem cells.Methods: Tca8113 cells were cultivated in SFM.The cells were morphologically observed under optical microscope.To induce the differentiation of spherical cells

tumor spheres were cultivated in SSM.The expression of aldehyde dehydrogenase(ALDH) of undifferentiated spherical cel1s

post-differentiated spherical cells and SSM cells were detected by the fluorescence-activated cell sorting.Results:In SFM consisting of EGF

bFGF

and B27

a minority of Tca8113 cells could survive

proliferate

and form the suspended tumor spheres.The tumor spheres highly expressed ALDH(0.297 0±0.009 0∶0.010 7±0.002 5) and also displayed differentiation-induced abilities.No significant difference in morphology was found between the post-diferentiated spheres cells and routine cultured Tca8113 cells.Conclusion:Tumor spheres with enriched cancer stem cells can be generated under serum-free culture condition with EGF

bFGF

and B27.