PROBLEM TO BE SOLVED: To provide a method enabling a cancer stem cell population to be efficiently isolated and cultivated reflecting a disease state of an intractable cancer or the like, and also to provide a method for preparing a xenograft, a screening method, a method for reducing a miR-34a expression quantity, and a cancer stem cell proliferation inhibitor.SOLUTION: The present invention relates to a preparation method of a cancer stem cell population. The preparation method comprises: implanting a cell mass containing a cancer stem cell into a non-human animal different from the species from which the stem cell is derived forming a xenograft in the non-human animal taking out the xenograft from the non-human animal and cultivating the xenograft in a serum-free three-dimensional culture medium containing a growth factor which promotes the fission of the cancer stem cell, thereby forming an organoid.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT【課題】難治性がんなどの病態を反映したがん幹細胞集団を効率的に分離・培養することができる方法を提供すること。異種移植片の調製方法、スクリーニング方法、miR-34aの発現量を低下させる方法及びがん幹細胞増殖抑制剤を提供すること。【解決手段】本発明は、がん幹細胞集団の調製方法である。調製方法は、がん幹細胞を含む細胞塊を、前記がん幹細胞の由来種とは異なる非ヒト動物に移植する工程と、該非ヒト動物において異種移植片を形成させる工程と、前記非ヒト動物から前記異種移植片を取り出す工程と、前記異種移植片を、前記がん幹細胞の分裂を促進させる増殖因子を含む無血清3次元培地において培養し、オルガノイドを形成する工程と、を有する。【選択図】図1
