PROBLEM TO BE SOLVED: To provide antitumor effect enhancers that can enhance the antitumor effect of MEK inhibitors and/or c-Met inhibitors, and to provide antitumor agents that exert excellent antitumor effect to various kinds of cancers.SOLUTION: The antitumor effect enhancer according to the present invention contains a coumarin derivative or a pharmaceutically acceptable salt thereof as an active ingredient, and can enhance the antitumor effect of MEK inhibitors and/or c-Met inhibitors.SELECTED DRAWING: Figure 17COPYRIGHT: (C)2016,JPO&INPIT【課題】ＭＥＫ阻害剤および／またはｃ－Ｍｅｔ阻害剤の抗腫瘍効果を増強しうる抗腫瘍効果増強剤、並びに、各種の癌に対し優れた抗腫瘍効果を奏する抗腫瘍剤を提供する。【解決手段】本発明に係る抗腫瘍効果増強剤は、クマリン誘導体またはその薬学的に許容される塩を有効成分として含有し、ＭＥＫ阻害剤および／またはｃ－Ｍｅｔ阻害剤の抗腫瘍効果を増強しうる。【選択図】図１７
