The subpopulations in cell lines obtained by sorting for in vitro and in vivo assays. Subpopulations including CD44+ CD24hi, CD44+ CD24-/lo, CD44+ CD24-/lo SSEA-3+, CD44+ CD24/lo SSEA-3−, various percentages of SSEA-3+ (top 1, 5, 10%), and SSEA-3− in MCF-7 (A), as well as ESAloPROCRlo, ESAhiPROCRhi, ESAhiPROCRhiSSEA-3+, ESAhiPROCRhiSSEA-3−, various percentages of SSEA-3+ (top 1, 5, 10%), and SSEA-3− in MDA-MB-231 (B), were enriched by cell staining (Materials and Methods) and flow cytometry for the further analysis.