Significance of CD90+ cancer stem cells in human liver cancer

This study characterized cancer stem cells (CSCs) in hepatocellular carcinoma (HCC) cell lines, tumor specimens, and blood samples. The CD90(+) cells, but not the CD90(-) cells, from HCC cell lines displayed tumorigenic capacity. All the tumor specimens and 91.6% of blood samples from liver cancer patients bore the CD45(-)CD90(+) population, which could generate tumor nodules in immunodeficient mice. The CD90(+)CD44(+) cells demonstrated a more aggressive phenotype than the CD90(+)CD44(-) counterpart and formed metastatic lesions in the lung of immunodeficient mice. CD44 blockade prevented the formation of local and metastatic tumor nodules by the CD90(+) cells. Differential gene expression profiles were identified in the CD45(-)CD90(+) and CD45(-)CD90(-) cells isolated from tissue and blood samples from liver cancer patients and controls.