Abstract: Objective To investigate new type cytokine induced killer cells expansion using advanced breast cancer's peripheral blood.Methods peripheral blood mononuclear cells were isolated from 8 advanced breast cancer volunteers and co-cultured with Cytokine induced killer cells.These cells were placed in plastic flasks containing CIK-MediumTM supplemented with 10% auto-plasma in the presence of IL-2(1000IU/mL).The cultures were fed with CIK-MediumTM supplemented with IL-2 following the proliferation capacity.Cell proliferation was measured by cell counting during the cultivation.Fourteen days after cultivation,cell markers CD3/CD16/CD56 were examined by flow cytometry.51Cr and MTT assays were employed in cytotoxicity assays.Cytokines were assayed by ELISA method.Results CD16⁺,CD16⁺ CD56⁺,CD56⁺ CIK cells were 5.8~11.6% in 2×10⁷ fresh PBMCs and 95.2~97.6% in co-cultured cells after 18 days cultivation.The in vitro expansion rate of new type cytokine induced killer cells was up to more than 8.2×10⁸ in total,the cytotoxicity are effective killing cells against MCF7 and BT20 breast cancer cell lines.New type cytokine induced killer cells expanded from all PBMCs and secreted cytokines IFN- and TNF-.Conclusion The present culture could be useful to clarify the mechanisms of CIK cells expansion in vitro and feasible for breast cancer immmuno cell therapy.