Abstract: The isolation and identification of cancer stem/progenitor cells from the ascites of ovarian cancer Patients WANG Cuihuan, GAO Yan, HE Xiaoying, DU Yongrui, YAO Zhi, DENG Weiming△Department of immunology, Tianjin Medical University, Tianjin 300070, China ? Abstract Objective: To isolate and identify the stem/progenitor cells from the ascites of ovarian cancer patients. Methods: To isolate ovarian cancer stem/progenitor cells by sphere-forming in serum-free culture medium and to identify the stemness of this kind of cell from following aspects: side population were detected by the flow-cytometry; to determine the expression of genes and proteins of the stem/progenitor cell-relevant markers ABCG2, Oct-4, Nanog in ascetic spheroid cells and ascetic cells by PCR and Western blot respectively; to evaluate the tumor-formation ability in the NOD/SCID mice. Results: The ascitic spheroid cells had unique growth characteristics, and SP cells accounted for 0.9% and 0.2% in ascitic spheroid cells and ascitic cells respectively. The ascitic spheroid cells expressed higher stem/progenitor cell-relevant markers ABCG2, Oct-4 and Nanog than ascitic cells; Furthermore，xenograft tumor formed only by 1×104 ascitic spheroid cells in NOD/SCID mice. Conclusions: The ovarian cancer stem/progenitor cells can be isolated by sphere-forming in serum-free culture medium from ascites and can be used as a potential tool for studying the pathogenesis and scanning the anti-cancer drugs in the treatment of human ovarian cancer. Key words ovarian cancer tumor stem/ progenitor cells isolation identification

Key words: ovarian cancer, tumor stem/ progenitor cells, isolation, identification