Figure 1: Chondrosphere formation and cytometric analyses. (A) Adherent, homogeneous chondrosarcoma cells. Scale bar = 400 μm; (B) Chondrosphere clusters were clearly observable already after 24 hours of culture in condrosphere medium. Scale bar = 400 μm; (C) Cells migrated from the spheres within a few hours of culture in standard culture-ware and adhered to the bottom of the flasks, assuming a polygonal shape. Scale bar = 200 μm; (D) Number of cells positive for OCT4, SOX2, CD133, and collagen type II in chondrospheres and adherent cells. All error bars represent 95% confidence intervals; ** p<0.005 compared with adherent cells.