Figure 1. MCF-7 tumourspheres exhibit self-renewal efficiency and long term culture potential.

Sphere forming efficiency progressively increases over serial passages (P). (a) Between P1 and P2 (t-test p = 0.0013, **), and between P6 and P8 (t-test p<0.0001, ***). (b) Sphere formation was dose dependent. Increasing the number of single cells plated in the sphere assay increased the total number of spheres formed. Sphere sizes range between 50 and 200 μm for day 5 spheres. (c) Growth curve showing total number of cells generated over 8 passages for matched adherent cells (open circles) compared to sphere-cultured cells (closed circles) demonstrating long-term culture capacity for spheres. Error bars represent standard error of the mean (SEM).