CEACAM7 and colon carcinoma: In addition, immunohistochemistry and immuno flow cytometry were used to demonstrate a good correlation between the Gold epitope groups and their binding specificity: 1) mAbs that bind to Gold epitopes 2 and 3 were generally specific to CEA, reacting only with colon carcinoma, normal colon mucosa and normal gastric foveola; 2) mAbs in epitopes 4 and 5 were highly cross-reactive with different normal tissues possibly due to binding to CEA-related antigens; and 3) both specific and cross-reactive mAbs were found in epitope 1 [56].