Abstract
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.
Highlights
carcinoembryonic antigen (CEA) in cytological brush specimens CEA was found by radioimmunoassay in the brush specimens of patients with both benign and malignant gastric lesions (Fig. 1)
In 2 tions > 10 nglpg DNA in gastric mucosal cancer patients CEA was immunohisto- brush specimens chemically detected in non-cancerous tissue, but not in malignant cells
The results presented here indicate immunoreactive CEA in both benign and malignant gastric mucosa
Summary
Determination of DNA.-TI-ie CEA content of the endoscopic brush specimens was correlated xiith the amount of DNA. Of the same specimens from which CEA had been determined, 0-2ml aliquots were taken for DNA determinations. The samples -%N-ere incubated AA-ith 20 tkl of a solution containing 10 .ug/ml DNase (Sigma) and 50 iLg/ml crude phosphodiesterase (Sigma) for 30 min at 37'C. Deoxyribose -%Aas determined fluorimetrically after reaction -%N-ith thiobarbituric acid. This method (Nordling, to be published) is a modification of a method to determine sialic acid described by Hammond & Papermaster (1976). The molecular weight of the immunoreactive CEA peak -was calculated according to the method of Laurent & Killander (1964) using blue dextran, human IgG, human serum albumin and ot-lactalbumin as reference proteins
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