Abstract
We investigated serologically and immunohistochemically the correlation between positive area of immunoreactivity in NCC-ST-439 (ST-439) antigen and the degree of clinicopathological factors and examined its utility as a tumor-associated antigen of colorectal cancer. The colorectal cancer tissue was removed surgically from 200 patients with colorectal cancer in our department. For the immunohistochemical examination, the streptoavidin-biotin (SAB) method was conducted with a specific monoclonal antibody. For measuring of the positive area, we used the CAS 200 Image Analyzer. The rates of an immunohistochemical expression of ST-439 were 81.6% for the apical and intraluminal types and 18.4% for the cytoplasmic type. The expression of ST-439 and the positive area in differentiated adenocarcinoma were higher than in undifferentiated adenocarcinoma. There was a close correlation among staging, depth of invasion, tumor diameter and lymph node metastasis, liver metastasis, peritoneal dissemination and positive area and expression of ST-439 antigen. These results demonstrated that the grade of the positive area and expression of ST-439 antigen were strongly associated with malignancy and prognosis of colorectal cancer. It is suggested that ST-439 antigen is useful as a tumor marker for colorectal cancer.
