Comparative analysis of CA72-4, CA195 and carcinoembryonic antigen in patients with gastrointestinal malignancies.

To establish further the clinical significance of the novel quantitative immunoradiometric assay system CA72-4 in patients with gastric and other digestive tract malignancies, the sera of a total of 208 subjects have been analysed and levels of carcinoembryonic antigen (CEA) and another promising new tumour marker, CA195, have been compared. Twenty patients had gastric (GC), 60 colorectal (CC), and 14 pancreatic carcinomas (CC); 94 patients had benign disorders, and 20 were healthy volunteers. CA72-4 elevations above normal (greater than 4 U/ml) were observed in 6 (30%) GC, 17 (28%) CC, and 8 (57%) PC patients. CA195 appeared more sensitive and was increased (greater than 10 U/ml) in 35% GC, 70% CC, and in 100% PC patients; CEA levels above normal (greater than 5 ng/ml) were noted in 35%, 45%, and 66% of patients respectively. CA72-4 had a rather high specificity and was increased in only 6/94 (6%) patients with benign diseases, whereas CA195 had a false positive rate of 23%, and CEA of 33%. Among 20 healthy donors, none had elevated levels of CA72-4 or CA195, but marginal elevations of CEA were noted in 3 smokers. Despite some advantage of the new tumour marker CA72-4 in terms of specificity, its value as a serodiagnostic test in gastrointestinal cancer patients seems inferior to that of CA195 and CEA.