PROBLEM TO BE SOLVED: To provide a compound used for treating and/or preventing cancer. SOLUTION: 6-(4-Tert-Butylphenoxy)Pyridin-3-Amine or one of its derivatives having Notch signal transduction pathway inhibitory properties, its salts, solvates, tautomers, isomers. [Selection diagram] None【課題】がんの治療及び/又は予防に使用される化合物の提供。【解決手段】6-(4-tert-ブチルフェノキシ)ピリジン-3-アミン又はNotchシグナル伝達経路阻害特性を有するその誘導体の1つ、その塩、溶媒和物、互変異性体、異性体。【選択図】なし