PROBLEM TO BE SOLVED: To provide the therapy and diagnosis method of colorectal tumor tissues, in particular, colon and stomach tumor tissues and metastatic tumors derived therefrom.SOLUTION: The present invention relates to an anti-sense oligonucleotide that inhibits the expression of nucleic acid encoding colorectal tumor antigen, in particular, colon and stomach tumor antigen, revealed to be expressed in colorectal tumor cells, in particular, colon and stomach tumor antigen. The present invention also relates to the therapy method of the tumor using an antibody specifically binding to the tumor antigen or a ligand or the like of a nucleic acid encoding the tumor antigen which a therapeutic effector moiety, such as a radiolabel, that binds to, and the diagnosis method using a monoclonal antibody and the like specifically binding to a peptide comprising the amino acid sequence of a tumor antigen peptide derived from the tumor antigen.SELECTED DRAWING: None【課題】結腸直腸腫瘍組織、特に大腸及び胃腫瘍組織、並びにそれらに由来する転移性腫瘍の治療及び診断法の提供。【解決手段】結腸直腸腫瘍細胞、特に大腸及び胃腫瘍細胞において発現することを明らかにした、結腸直腸腫瘍抗原、特に大腸及び胃腫瘍抗原をコードする核酸の発現を阻害するアンチセンスオリゴヌクレオチド，該腫瘍抗原に特異的に結合する抗体、又は放射性標識等の治療効果分子が結合した該腫瘍抗原をコードする核酸のリガンド等を用いる該腫瘍の治療法，及び該腫瘍抗原に由来する腫瘍抗原ペプチドのアミノ酸配列を含むペプチドに特異的に結合する、モクロナール抗体等を用いる診断法。【選択図】なし
