Figure 2

Only the CD44^hi/CD24^lo A4 and the parental HMT3909S13 cell lines initiated tumors in immunodeficient mice. (A) Tumor formation upon orthotopic inoculation into the mammary fat pad of CD44^hi/CD24⁻ G4, CD44^hi/CD24^lo A4, HMT3909S13 or Hs578T cells into two strains of immunodeficient mice (CB17-SCID and NOG). Ratios refer to the number of mice in which primary tumors developed relative to total number of mice inoculated with cells within each group. (B) Tumors established after orthotopic inoculation of 10⁴ A4 cells in a NOG mouse (right, arrow), whereas no tumor formation was observed in any of the NOG mice orthotopically inoculated by 10⁶ G4 cells (left). (C) Whole-body bioluminescent imaging of lung metastases established after tail vein inoculation of 10⁶ Luc2-transfected A4 or G4 cells.