Localization of Monoclonal Antibody CC49 in Colonic Metastasis from Renal Cell Carcinoma

We report a rare case of solitary metastasis from renal cell carcinoma which manifested as a primary colonic tumour 5 years after nephrectomy. A monoclonal antibody CC49 (anti-TAG-72 antibody), used in Radioimmunoguided Surgery, was found to localize in the tumour. Pathological examination revealed metastasis of renal cell carcinoma in the colon. Immunohistochemistry with CC49 showed moderate staining of the colonic mucosa around the metastasis with no reaction in the tumour itself. Based on this case and other published studies, we conclude that TAG-72, the antigen manifested in many adenocarcinomas, can be up-regulated and expressed in normal colonic mucosa adjacent to another tumour as a result of stimulations, such as cytokine release, in response to this tumour.