Difference of Self-renewal and Tumorigenicity among Different Breast Cancer Stem Cells Subpopulations

Objective To analyze the difference of self-renewal and tumorigenicity among different breast cancer stem cells subpopulations. Methods CD44⁺CD24-/low, ALDH1⁺ and ALDH1⁺CD44⁺CD24-/low cells populations were isolated from fresh breast cancer tissues by flow cytometry analysis and the percentage of each isolated cells in total tumor cells were calculated. By clone formation and immunofluorescence experiments, the capacities of self-renew of each subpopulation cells were analyzed. We utilized the mouse model to observe the tumorigenicity of the three different subgroups. Results The subpopulations of CD44⁺CD24^-/low, ALDH1⁺and ALDH1⁺CD44⁺CD24^-/low accounted for 7.2%, 4.6% and 1.5% of total tumor cells respectively. ALDH1⁺CD44⁺CD24^-/low subpopulation had the strongest capacity of self-renewal and tumorigenicity, while CD44⁺CD24^-/low phenotype breast cancer cells were proved to be the weakest (P<0.05). Conclusion ALDH1⁺CD44⁺CD24^-/low subpopulation have the strongest capacity of self-renewal and tumorigenicity than CD44⁺CD24^-/low and ALDH1⁺, which suggests that ALDH1⁺CD44⁺CD24^-/low could be a more specific marker of breast cancer stem cells.