Comparative evaluation of carcinoembryonic antigen, secretory component, and mucins in index and metachronous adenomas of the colorectum.

Of 124 patients who underwent endoscopic polypectomy, 70 were colonoscopically reevaluated during a mean period of 10 years. On the basis of the clinical outcome, the patients were divided into three groups: group 1, 31 patients who had a colon still with no adenomas or cancer; group 2, 35 patients in whom one or more metachronous adenomatous polyps developed; and group 3, 4 patients in whom a carcinoma of the colon subsequently developed. In addition to the clinical and pathological features, the pattern of the immunohistologic staining for carcinoembryonic antigen and secretory component was studied. Moreover, the mucin histochemical staining intensity of neutral mucins, sulfomucins, and sialomucins was evaluated. The features of the 40 index adenomas obtained from patients in group 1 were compared with the features of the 51 index adenomas from patients in group 2. Furthermore, these characteristics of the index adenomas were compared with those in the 69 metachronous adenomas of the group 2 patients. It was found that male sex (P less than 0.005) and a history of colorectal neoplasia (P less than 0.02) are main factors for the development of new adenomas. The neutral mucins were less abundant in the group 2 index adenomas (r = -0.21; P less than 0.05). The expression of the other evaluated markers was not significantly different between both groups, although the group 2 index adenomas were significantly smaller (r = -0.22; P less than 0.05) and showed a trend toward a more pronounced cytoplasmic expression of carcinoembryonic antigen than the index adenomas from group 1 (22% vs. 12.5%). Moreover, it was found that in comparison with the index adenomas, metachronous adenomas were significantly smaller (r = -0.24; P less than 0.01) and more sessile (r = 0.20; P less than 0.002). Significant negative correlations, i.e., decrease, were also found in the expression of carcinoembryonic antigen (surface P less than 0.001; cytoplasmic P less than 0.05) and neutral mucins (P less than 0.005) between the index adenomas and the metachronous adenomas, whereas positive correlations were found for secretory component (P = 0.0001) and sulfomucins (P less than 0.05). These findings suggest that a limited production of neutral mucins in the goblet cells of a small index adenoma from a male patient with a history of colorectal neoplasia is indicative of an increased risk for the development of new colorectal adenomas. Furthermore, the clinical, mucin histochemical, and immunohistochemical findings of the metachronous adenomas show less malignancy-associated features than those of the index adenomas.