Carcinoembryonic antigen and carcinoids of the gastrointestinal tract.

We studied the prognostic significance of immunohistochemically localized carcinoembryonic antigen in 131 nonmetastasizing and 35 metastasizing gastrointestinal carcinoid tumors. The rate of positivity was lower with preabsorbed versus nonabsorbed polyclonal antiserum. Compared with generally used prognostic features (depth of invasion, tumor size, and mitotic rate) positivity for absorbed anticarcinoembryonic antigen was the most specific feature for metastatic tumors but was least sensitive. Although our results demonstrate that anticarcinoembryonic antigen, particularly when absorbed, is highly associated with metastatic disease, depth of invasion and tumor size are better predictors of behavior.