Figure 1

Stem cell properties of BCSCs. ESA⁺CD44⁺CD24^-/lowlineage^- human BCSCs (corresponding to 1.5% of cancer cells) were isolated by flow cytometry (A). Under an inverted phase contrast microscope, the ESA⁺CD44⁺CD24^-/low grew into globular colonies (B). Xenograft tumors in NOD/SCID mice are shown (C). From left to right, tumors developed from 5 × 10⁵ and 5 × 10⁶ MCF-7 cells and from 5 × 10³ and 5 × 10⁴ BCSCs.