Analysis for factors determining cancer stem cells ; aiming for their visualization

为了对癌症干细胞进行可视化，我们首先确定了癌症细胞系侧群中高表达的分子，已知其中包含癌症干细胞。我们在乳腺癌细胞系MCIF7的侧群中分离到了几个高表达的候选分子，如CD55。CD55高表达的细胞大量表达抗凋亡分子，体外集落形成效率更高。在对NOD/SCID小鼠的移植中，CD55高特性的细胞比CD55低特性的细胞更具致瘤性。此外，我们还发现，与CD55高表达肿瘤细胞稀少的乳腺癌相比，CD55高表达肿瘤细胞丰富的乳腺癌患者预后较差。这表明肿瘤干细胞的数量可能决定肿瘤的预后。除了CD55，我们还发现了几个分子，如Notch2，可以作为淋巴瘤细胞系致瘤细胞的标志。

To aim for visualization of cancer stem cells, we first determined the molecules highly expressed in the side population of cancer cell lines, in which cancer stem cells are known to be contained. We isolated several candidates of molecules highly eapiessod in side population of breast cancer cell line MCIF7, such as CD55. Cells with CD55-high character expressed anti-apoptotic molecules abundantly, and formed colonies in vitro more efficiently. In the transplantation to NOD/Scid mice, cells with CD55-high character were more tumorigenic than cells with CD55-low character. In addition, we found breast cancer cases with ample CD55-high tumor cells showed poor prognosis as compared to the caces with scarce CD55-high tumor cells. These showed that the quantity of cancer stem cells might determine the prognosis of tumors. Besides CD55, we found several molecules, such as Notch2, would be a marker for tumorigenic cells of lymphoma cell line.