Fig 3. MG63 OS cells form spheres and their number is increased by the presence of MSC.

(A) Homotypic cultures of CSC and their co-culture with MSC for 6 days were photographed at a magnification of 4x, representative images (scale bar 500 μm, black arrows show the spheres with higher size); (B) spheres were counted and expressed as sphere forming efficiency (number of spheres formed / number of cells seeded × 100) (*p<0.05).