Objective   To isolate and identify ovarian cancer stem cells from ovarian cancer cell line A2780.   Methods   The A2780 cells were cultured in serum-free medium with EGF

bFGF

insulin and BSA to induce tumor stem cells by continuous passage. Flow cytometry was applied to identify the cancer stem cells in every passage. Immunofluorescence staining and reverse differentiation experiments were conducted on the fourth passage of cancer stem cells.   Results   The ovarian cancer stem cells were successfully isolated from ovarian cancer cell line A2780. They formed typical neurospheres in serum-free medium

and had strong self-renew capacity. The results of flow cy

tometry illustrated that CD133 positive rate was increased with the passages of cancer stem cells. Immunofluorescence staining further confirmed that CD133

+

cells were the surface marker of ovarian cancer stem cells

and they could differentiate into ovarian cancer cells in reverse differentiation experiments.   Conclusion   There were ovarian cancer stem cells in ovarian cancer cell line A2780

which can be isolated

cultured and differentiated.