MCF-7 cell growth in three-dimensional culture. 1×105, 3×105, and 5×105 cells were cultured in DMEM containing 10% FBS in the three-dimensional matrigel (5 mg/ml) for 24 h and then CD24 was cross-linked with 500 ng/ml anti-rabbit polyclonal IgG or anti-human CD24 rabbit polyclonal antibody for 72 h. Cell viability in three-dimensional culture was examined by MTT assay. The data are shown as the absorbance of MCF-7 survival versus the control cell survival after CD24 cross-linking with anti-rabbit polyclonal IgG. Means of at least three independent experiments are compared and standard errors are shown. *, p value of less than 0.05.