AIMS The CAS0 and CEA are well-described human tumor-as- sociated antigens most useful clinically in gastrointestinal cancer. In this study we compared these markers in sera from patients with malignant and benign digestive tract diseases. METHODS Using a side-phase radioimmunoassay,CA50 and CEA serum levels were measured in 33 control subjects and 86 patients with gastric cancer(n=34),gastric ulcer(n=27)and chronic atrophic gastritis(n=25).Carcinoma of the stomach was found in the antrum(n=22),in the body(n=3),and the fundus(n=9),and histopathologically,was divided into adeno- carcinoma(n=21),squamous cancer(n=4)and not divided (n=9).Gastric ulcer,when present,appeared in the antrun(18 patients),the body(3)and the fundus(9)and chronic atrophic gastritis was all associated with intestinal metaplasia(IM). RESULTS The normal ranges established for CA50 and CEA in the control group were 16.26+6.14 kU/L and 3.12±1.03/μg/L respectively.In the patients with gastric cancer,serum levels of CA50(112.67±38.36 kU/L)and CEA(10.28±3.76μg/L) were elevated significantly(P<0.01,respectively),the former being>22 kU/L in 18 of 34 patients(53%;range,5-1 550 kU/ L),and the latter>5 μg/L in 19 of 34 patients(55.8%,range, 0.5-17.4 μg/L).A statistically significant correlation was found between the levels of CA50 and GEA(r=0.648,P<0.01). The serum levels of CA50(46.4±25.9 kU/L,P<0.01 )and CEA(6.85±2.43 μg/L,P<0.01)were much lower in patients with gastric ulcer or chronic atrophic gastritis(P>0.05). CONCLUSIONS Based on these results,it is concluded that CA50 and CEA are indicators for advanced gastric cancer,and af- ter surgery,their serum levels may decrease considerably. Overall,there is such a close correlation between them that in clinical practice they might be of great value to the diagnosis of gastric cancer.
