Figure 4

Flow cytometric analysis of CD44 expression. Cells were stained with APC-conjugated anti-CD44 antibody ( A ) or un-labeled anti-CD44 variant antibody followed by FITC-conjugated mouse anti-rat IgG antibody ( B to D ) and then separated with a flow cytometer. The positive for CD44s population in cells with sphere-forming potential, SK-sphere and HLE-sphere, were higher than those in non-sphere-forming cells ( A ). B and C, representative flow cytometry histograms of SK-HEP-1 and SK-sphere cells, respectively. Black and gray histograms represent cells stained with anti-CD44v and isotype control antibodies, respectively. D, bar-chart summarized from independent flow cytometric experiments. Sphere cells, SK-sphere and HLE-sphere, showed an increased population of CD44v positive cells compared to their parental cells ( D ). **P < 0.05 with the Mann-Whitney U-test.