PROBLEM TO BE SOLVED: To provide inhibitors of Notch signalling pathway in treating and/or preventing cancers.SOLUTION: The present invention relates to 6-(4-tert-butylphenoxy)pyridin-3-amine of the following formula, used in treating and/or preventing cancers.SELECTED DRAWING: None【課題】がんの治療及び/又は予防におけるNotchシグナル伝達経路の阻害剤の提供。【解決手段】がんの治療及び/又は予防に使用される、下記式の6-(4-tert-ブチルフェノキシ)ピリジン-3-アミン。【選択図】なし