FIG. 5.

Tumorigenicity by cloned CD34+ LCSC. (A) The ability of the cells to form tumors in vivo was evaluated by the injection of the same numbers of sorted CD34+ PLC and cloned CD34+ LCSCs from the 5th passage (p5) to the 18th passage (p18) into NOD/SCID/IL2rg mice. (B) The tumors were formed within 2 months, and the number and the timing of tumor formation were not different between these four groups. Hematoxylin and eosin staining of human xenografts produced by the injection of cloned CD34+ LCSC into mice, exhibited the typical histologic features of human liver carcinomas, including polygonal cells with pleomorphic nuclei in cells with distinct cell borders; the increased nucleus:cytoplasm ratios; the presence of endothelial cells lining the sinusoids (single black arrow); small and large foci of necrosis (double black arrows) and dilated blood vessels (single white arrow); nested growth pattern with large tumor nodules separated by a thick fibrous band (double white arrows); various components of hepatocytes such as lipids and other cytoplasmic constituents (black head arrow). (C) Human liver-specific proteins, hepatocyte-specific antigen-Hep Par1, CK19, alpha 1-antitrypsin (α1-AT), and liver cancer marker, EpCAM were expressed in the tissues of aforementioned human xenografts. The specificity of primary antibodies was evaluated by employing isotype controls. Scale bar, 100 μm. Color images available online at www.liebertpub.com/scd