The proportion of CD44+CD24− cell subsets in the serum‐free suspension culture of MCF‐7‐CSC was significantly higher than that of MCF‐7 (P < 0.05) (Figure 1B), indicating that the presence of surface markers of breast cancer stem cells in MCF‐7‐CSC had increased significantly than that of in MCF‐7. The gene discussed is CD44; the disease is breast cancer.