Provided are a method and a pharmaceutical composition for treating cancer using a compound having VAP-1 inhibitory activity or a pharmaceutically acceptable salt thereof. Also provided are combination use of the compound having VAP-1 inhibitory activity or a pharmaceutically acceptable salt thereof and an anti-CTLA-4 antibody, and combination use of the compound having VAP-1 inhibitory activity or a pharmaceutically acceptable salt thereof, an anti-CTLA-4 antibody and an anti-PD-1 antibody.本發明提供一種使用具有VAP-1抑制活性之化合物或其醫藥上可接受之鹽治療癌症之方法與醫藥組成物。亦提供該具有VAP-1抑制活性之化合物或其醫藥上可接受之鹽與抗-CTLA-4抗體之組合用途,及該具有VAP-1抑制活性之化合物或其醫藥上可接受之鹽、抗-CTLA-4抗體與抗-PD-1抗體之組合用途。