The occurrence of carcinoembryonic antigen (CEA) was studied in 45 cases of gastric tumors by the immunoperoxidase technique. CEA-positive staining was found in 48.8% of tumors. A correlation was found between preoperative CEA values and tumor CEA staining. All patients with serum CEA values below 2.5 ng/ml showed CEA-negative staining of tumor. In patients with serum CEA values between 2.6 and 10 ng/ml, the tumors showed a minority of CEA-positive cells; but in patients with serum CEA values above 10 ng/ml, the tumors contained a majority of CEA-positive cells. CEA-positive staining was found in 34.4% of tumors of the diffuse type, and in 75% of tumors of the intestinal type. A high percentage of CEA positivity was seen in well-differentiated tumors (87.7%) compared to the moderately differentiated (69.2%), and to the undifferentiated (28.7%). A faint CEA-positivity was observed in intestinal metaplasia, while normal gastric mucosa was CEA-negative.

In order to demonstrate a prognostic value of preoperative CEA levels, we have tried to define a correlation between CEA and histologic stage of tumor in 124 patients with colorectal carcinoma. CEA concentration has been evaluated by radioimmunologic assay and the histologic stage following Dukes' classification. The results show a 25.0% positivity rate for patients in stage A, 48.2% for stage B, 61.1% for stage C, and 85.7% for stage D. The mean CEA values are 7.8 ng/ml in the first group, 30.3 ng/ml in the second, 58.1 ng/ml in the third, and 134.3 ng/ml in the last group. Furthermore, we have tried to relate the histopathologic grade of the tumor (G) with CEA levels in 54 patients of the 124. We conclude that preoperative CEA has a prognostic value, and it is useful in the staging of colorectal cancer patients. A low concentration indicates an early stage of the tumor, while a high concentration indicates a wide spread of disease; on the other hand, there are not significant correlations with cancer grading.

The evaluation of serial plasma carcinoembryonic antigen (CEA) levels is one of the most important parameter used to establish the prognosis of surgically cured colorectal cancer patients. Carcinoembryonic antigen is particularly useful in the identification of recurrences and metastasis. However, to improve the usefulness of this assay, it would be helpful to accurately determine, if possible, those patients whose cancers produce CEA. The evaluation of the presence of CEA in these cancer specimens by means of immunoperoxidase staining technique does seem to improve the sensitivity of the CEA test. Fifty‐seven patients with colorectal cancer who underwent surgical treatment were studied. Tissue CEA evaluation was correlated with the plasma CEA levels, the pathologic stage and grade, and histologic type of the cancers. Results demonstrate that 66.6% of Dukes' B cancers, 78.9% of Dukes' C, and 77.7% of Dukes' D cancers stained positively for CEA by immunoperoxidase. Thirty of 57 patients with preoperative pathologic plasma CEA levels had positive tissue CEA, whereas 8/57 patients did not. Of patients with a well‐differentiated cancer (G1), 81.4% had positive tissue CEA versus the 64% of G2 and 60% of G3 cancers. The authors conclude that the use of the immunoperoxidase stain to measure CEA in tissue, so that the CEA serum assay may be used in those patients known to produce CEA, results in a major increase in the sensitivity of the test.

We study the presence of Carcinoembryonic antigen (CEA) on 39 colorectal polyps by the immunoperoxidase technique. The histological examination demonstrated 15 tubular adenomas, one villous adenoma, two tubulo-villous adenomas, six tubular adenomas with slight dysplasia, one tubular adenoma with moderate dysplasia, four tubular adenomas with severe dysplasia, three tubulo-villous adenomas with severe dysplasia, five tubular adenomas with neoplastic degeneration, and two tubulo-villous adenomas with neoplastic degeneration. Twenty-eight of thirty-nine polyps (71.79%) showed a positive staining reaction for CEA. Regarding the intensity of the reaction (classified as absent or negative [-], slightly positive [+], and markedly positive [+ +]), 11/39 polyps presented a negative reaction (28.21%), 19/39 (48.71%) presented a slight reaction, and 10/39 polyps (25.64%) presented a marked reaction. Results demonstrated a higher intensity of the staining reaction in severely dysplastic polyps and in neoplastic degeneration. In conclusion, it is possible that the presence of CEA can be useful to show an initial cellular restlessness of certain polyps.