To study the effect of Stigmasterol on breast cancer stem cells, we established model stem cell-like spheroids from two types of breast cancer cell lines 4T1 and SUM159 with stem properties marker CD44+CD24-/low by flow cytometry and determined the expressed CD44 and CD24 in these selected breast stem cells with Immunofluorescence assay, as shown in Fig. 1A, CD24 remains low level and CD44 exhibits high level in these cells. This evidence concerns the gene CD44 and breast cancer.