Figure 2: Tracking of clonal expansion of cancer stem cells. Multicolor spheres cultivated in bulk (A, top). Magnified microscopic image of a multicolor single-sphere cultivated in bulk (A, bottom). Monocolor spheres cultivated in the nano-volume well chip in ULA conditions (B, upper panel). Magnified microscopic image of a single-sphere cultivated in the nanovolume well chip (B, lower panel). Table depicting the percentage of true monoclonal spheres and multicolor spheres (formed by 2, 3 or 4 colors), respectively, for conventional and nano-volume wells (C). Monoclonal spheres generated in the nano-volume well chip using either Matrigel™ (A) or methylcellulose (B). In all images, the different colors represent distinct fluorescent reporter genes: GFP (green), Katuschka (red), CAE (blue), and CIT (yellow).