To provide a novel anti-cancer agent which is directed to cancer stem cells for not only treatment of the primary cancer, but also prevention of metastasis and recurrence of cancer, for a purpose of complete cure, and which may kill the cancer stem cells.SOLUTION: There is provided an anti-cancer agent which inhibits spheroid formation in cancer stem cells. There is also provided a pharmaceutical composition containing such anti-cancer agent. According to the present invention, it is possible to provide a novel anti-cancer agent that inhibits spheroid formation of cancer stem cells having poor proliferation ability. In addition, there is also provided an anti-cancer agent effective for triple negative breast cancer, which has been difficult to treat conventionally.SELECTED DRAWING: None【課題】初発がんの治療だけでなく、がんの転移・再発を防ぎ、根治するために、がん幹細胞を標的とし、がん幹細胞を死滅させることのできる新たな抗がん剤を提供する。【解決手段】がん幹細胞のスフェロイド形成を阻害することを特徴とする抗がん剤、及びこのような抗がん剤を含有する医薬組成物を提供する。本発明により、増殖能の低いがん幹細胞のスフェロイド形成を阻害する新たな抗がん剤の提供が可能となった。また、従来治療が困難であったトリプルネガティブタイプの乳がんに対しても有効な抗がん剤が提供される。【選択図】なし
