Carbohydrate antigen 19-9 in tissues and sera from patients with gastric cancer

Detection of carbohydrate antigen (CA) 19-9 in tissues and sera was performed by an immunoperoxidase assay and by radioimmunoassay of samples from patients with gastric cancer. Twenty-eight of 102 (27.5%) gastrectomized patients and 13 of 21 (44.8%) patients with recurrent cancer showed abnormal and elevated levels of CA 19-9 in sera of more than 37 U/ml. Sixty-five of 102 (63.7%) patients gave positive localizations of CA 19-9 in cancerous tissues and 20 of 102 (19.6%) gave positive localizations of CA 19-9 in noncancerous gastric mucosa. Twenty-five of 28 (89.3%) patients with elevated serum CA 19-9 showed positive evidence of CA 19-9 in cancerous tissues, and 37 of 74 (50.0%) patients with normal serum levels of CA 19-9 also showed positive evidence of CA 19-9 in cancerous tissues. However, there were no clear relationships between CA 19-9 in cancerous tissues or in sera and the stage or histological type of the gastric cancer. These data indicate that CA 19-9 may be not released easily into blood circulation or that the concentration of CA 19-9 in tissues may be low, even though a large proportion of gastric cancer cells produces CA 19-9. It appears, therefore, that CA 19-9 will be restricted clinical use as a detector, monitor or tumor-associated antigen of gastric cancer.