PROBLEM TO BE SOLVED: To provide a novel means useful for the treatment and prevention of cancer, and to provide a novel therapeutic/prophylactic means effective even for cancer that is resistant to anti-cancer agents.SOLUTION: ErbB2 is identified as a cell membrane receptor for CCN2. A first therapeutic or prophylactic agent for cancer includes a substance capable of inhibiting the interaction between CCN2 and ErbB2 (a CCN2-ErbB2 interaction inhibitor) as an active ingredient. A second therapeutic or prophylactic agent for cancer includes a CCN2-ErbB2 interaction inhibitor as an active ingredient and is used in combination with an anti-cancer agent capable of inducing apoptosis.【課題】がんの治療及び予防に有用な新規な手段を提供すること、及び抗がん剤に耐性化したがんに対しても有効な新規な治療・予防手段を提供すること。【解決手段】本願発明者らは、鋭意研究の結果、CCN2の細胞膜受容体としてErbB2を同定した。本発明の第１のがんの治療又は予防剤は、CCN2とErbB2との間の相互作用を阻害する物質（CCN2-ErbB2相互作用阻害剤）を有効成分とする。本発明の第２のがんの治療又は予防剤は、CCN2-ErbB2相互作用阻害剤を有効成分とし、アポトーシスを誘導する抗がん剤と組み合わせて用いられる。【選択図】図１
