Sphere formation and proliferative capacity of H460 SP and non-SP cells.

<p>A–B, Purified SP and non-SP cells were cultured in serum-free medium in anchorage-independent conditions. The SP cells formed typical floating spheres within 4 days (A) whereas the non-SP cells largely established adherent growth (B). C, The SP cells displayed higher proliferative ability than non-SP cells as determined by CCK-8 kit (<i>P</i><0.05 for all time points, Student <i>t</i>-test).