Objective      To isolate and culture cancer stem-like cells (CSCs) from human lung cancer cell line H1299

and then identify their stem cell characteristics.       Methods      H1299 cells were cultured in serum-free medium under non-adherent conditions to induce the formation of tumorspheres. Immunofluorescent assay

flow cytometery

PCR and Western blotting were performed to evaluate the expression of CSCs markers

CD133 and ABCG2. The clonality and tumorigenicity in vivo were also examined.       Results      The tumorspheres were formed by sphere-forming culturing. The data demonstrated that there were stronger capacities of proliferation and tumorigencity in the tumorspheres derived from H1299 cells than the adherent cells. And the expression levels of CD133 and ABCG2 were significantly higher in the tumorspheres (P0.05).       Conclusion      The tumorspheres derived from H1299 cells by floating spheres culturing in serum-free condition are of high expression of CD133 and ABCG2

and possess stem cell characteristics.