Carcinoembryonic antigen in endoscopic brush specimens from benign and malignant gastric lesions.

The measurement of carcinoembryonic antigen (CEA) in serum and endoscopic brush specimens was evaluated for the differential diagnosis of malignant and nonmalignant gastric disease. Brush specimens were studied from 33 patients with gastric cancer and 36 patients with benign gastric lesions or apparently normal gastric mucosa. Demonstrable CEA immunoreactivity was found by radioimmunoassay in brush specimens from 24/33 cancer patients (73%) and from 23/36 patients with benign lesions (64%). Patients with CEA+ tissue in the immunoperoxidase test had somewhat higher CEA concentrations in the brush specimens than cases with CEA- biopsy tissue, although overlap was considerable. Thirty-five per cent of cancer patients had both a positive tissue CEA reaction and a CEA/DNA ratio greater than 10 ng/micrograms, whilst patients with benign lesions had only 15% of positives by these criteria (0.01 greater than P greater than 0.001). The serum CEA concentration was above the upper normal level of 5 ng/ml in 2/39 patients, both of whom had gastric cancer. The CEA immunoreactive material from benign and malignant lesions eluted in gel filtration on Sephadex G-200 in the same volume as CEA purified from liver metastases of cancer of the colon, showing that a glycoprotein sharing immunological and physicochemical properties with CEA is present both in malignant and nonmalignant lesions of the gastric mucosa, and that there is considerable overlapping in the amount of CEA. The estimation of CEA in gastric-brush specimens is therefore of limited value in the differential diagnosis of benign and malignant gastric lesions.