Using the magnetic bead method, we isolated CD133 + cells (Fig. 1A) from tissue samples of ten non-small cell lung cancer (NSCLC) patients (Table 1 ) and five lung cancer (LC) cell lines ( Table S1 ). The high percentage (97%) of CD133 + (LC-CD133 + ) subset was isolated in the LC tissues and parental LC cell line (Fig. 1A) . It has been reported that cancer stem-like cells can be cultured in suspension to generate floating spheroid-like bodies (SB) under serum-free medium with bFGF & EGF [30] . We found that LC-CD133 + isolated from these ten patients (Table 1 ) and five LC cell lines (Table S1 ) can form SB in DF-12 serum-free medium with bFGF and EGF ( Fig. 1B 1C ) and proliferation rate (Fig. 1D ) in LC-CD133 + were significantly higher than that in LC-CD133 2 (p,0.05). In addition, to determine the in vivo tumorigenic activity of LC-CD133 + and LC-CD133 2 , we injected respective amounts of 1000, 3000, and 10 4 cells into the tail veins of SCID mice. The results showed that 10 4 LC-CD133 2 did not induce tumor formation but 3,000 LC-CD133 + from the lung cancer tissues of ten patients and five LC cell lines in xenotransplanted mice can all generate visible tumors 4 weeks after injection (Table 1 and Table S1 ).