PROBLEM TO BE SOLVED: To provide an agent that inhibits cancer proliferation through the recovery of an immune function, and further an activation mechanism.SOLUTION: A cancer treatment agent comprises the substance that inhibits the suppressive signal induced by PD-1, PD-L1, or PD-L2, particularly an anti PD-1 antibody that inhibits the immunosuppressive signal of the PD-1, as an active ingredient. The PD-1 antibody is useful for the treatment of lung cancer.【課題】免疫機能の回復、さらには賦活機構を介して癌の増殖を阻害する薬剤の提供。【解決手段】ＰＤ－１、ＰＤ－Ｌ１、又はＰＤ－Ｌ２による抑制シグナルを阻害する物質、特にＰＤ－１の免疫抑制シグナルを阻害する抗ＰＤ－１抗体、を有効成分として含む癌治療剤。【効果】ＰＤ－１抗体は肺癌に対する治療に有用である。【選択図】なし
