Fig. 1

CR-1^high cells possess stemness properties compared to CR-1^low cells. a Representative flow cytometric histogram of the percentage of CR-1^high cells in EC109 cells. b qRT-PCR analysis showed that CR-1 ^high cells highly express stemness-related transcription factors Sox2, Oct4 and Nanog. c Limiting dilution assay showed that CR-1 ^high cells possessed higher capability of sphere formation than CR-1 ^low cells. d Colony formation of CR-1^high cells was stronger than CR-1^low cells (left: crystal violet staining, right: quantitative analysis). e Confocal microscopic analysis revealed that CK18 expression was up-regulated in CR-1^high cells after inducing differentiation for 7 days. f Subcutaneously xenografted tumor model indicated that tumors derived from CR-1^high cells were larger than those from CR-1^low cells (left). The histological origination of xenografts was confirmed by H&E staining (right). g The weight of the xenografts derived from CR-1^low and CR-1^high cells. Bar, 10 μm; * indicates p < 0.05; ** indicates p < 0.01