Abstract: Objective Under culturing different human breast cancer cell lines and the related content of cancer stem-like cells,we discuse CD44⁺CD24^-/low cell proportion in breast cancer cell lines and related subsets enrichment method of breast cancer stem-like cells through effective intervention of the commonly chemotherapy and flow cytometric analysis.Methods Through the cell culture of breast cancer cell line“MCF - 7,MDA - MB -231”,we observed the growth curve and compared grow under conditions with chemotherapy drugs intervention.we detected the expression proportion of CD44⁺CD24^-/low cell in the two breast cancer cell lines by flow cytometry.Under suspension culturing the above cell lines in serum-free medium,we observed clonal nonadherent spherical clusters by combining with or without chemotherapy scheme of TA scheme(docetaxel+table doxorubicin).Results 1.The multiplial time of MDA-MB-231 cells was shorter,and its growth rate was higher than MCF - 7 cells.2.The MCF-7 cells might exist the larger proportion of cancer stem-like cells with chemotherapy resistance and self-update.3.Chemotherapy sensitivity with two independent sample t-test,the result in MCF-7 cells suggested no statistical significance(P＞0.05).The result in MDA-MB-231 cells showed obvious positive significance(P＜0.05).MDA-MB-231 cells were more sensitive to chemotherapy from them.4.Under serum-free suspension cultures of two breast cell lines,MDA-MB-231 cells got no clear cell balls.MCF-7 cells were found cell balls at the first 6 day.With chemotherapy,the majority of the two tumor cells gradually died,and there were no living cell balls.5.Measured the content of CD44⁺CD24^-/lowcytometry cells by flow cytometry,the two above cell lines mainly contain CD44+CD24+ subsets(74.2%,95.7%)and CD44-CD24+ subsets(23.3%,3.95%).The CD44⁺CD24^-/low proportion of MCF-7 and MDA-MB-231 was 2.07%and 0.20%,respectirely.Conclusion 1.The MDA-MB-231 cells line which growed faster had higher malignant degree and showed more sensitive than MCF-7 cells line to TA chemotherapy scheme.2.Under serum-free suspension cultures,MCF-7 cells grow clonal monadherent spherical clusters,and the two lines had small proportion of CD44⁺CD24^-/low cell with flow cytometric detection.3.The CD44⁺CD24^-/low phenotype may not be the only specific surface markers of breast cancer stem cells.