We subsequently demonstrated increased expression of ABCG2 (Figure 4C) and recognised embryonic/pluripotent stem cell markers Nanog, Notch1 and SOX2 (Figure 4D–F), which have been associated with tumorigenesis [30], using real time PCR in the tumours formed following the injection of ABCG2hi SP cells compared with the residual cell pellets harvested from mice injected with ABCG2low NSP cells. The gene discussed is SOX2; the disease is neoplasm.