Abstract: [Problem] To provide a composition and a cell sheet which are highly effective for inhibiting fibrosis, or cells having fibrosis-inhibiting activity, which are useful in regenerative medicine. [Solution] A medium containing IC-2 or a related compound is inoculated with mesenchymal stem cells or bone marrow mononuclear cells, and the cells are cultured for a prescribed period of time while the IC-2 or related compound is maintained at a constant concentration, thereby allowing a composition and a cell sheet which are highly effective for inhibiting fibrosis, or cultured cells having fibrosis-inhibiting activity, to be obtained.

Abstract: A novel therapeutic drug for malignant tumors, cancer stem cells, or fibrosis is obtained. A therapeutic drug for malignant tumors or cancer stem cells is used that includes at least one compound selected from the group consisting of compounds represented by formulas (1), (2), and (5), a salt thereof, or a solvate thereof. Alternatively, a therapeutic drug for fibrosis can be used that includes at least one compound selected from the group consisting of compounds represented by formulas (1), (2), and (5), a salt thereof, or a solvate thereof.

Abstract: To obtain a novel therapeutic drug for a malignant tumor or fibrosis. Used is a compound represented by formula (1), a salt thereof, or a solvate thereof. Also used is a therapeutic drug for a malignant tumor or a therapeutic drug for fibrosis, comprising a compound represented by formula (1), a salt thereof, or a solvate thereof.