Serum CA 195 and CA 242 levels of patients with malignant gastrointest
inal tract (n=60) were determined in parallel with CEA and CA 19.9. Al
l markers showed low to moderate sensitivity for the malignant state.
In terms of specificity and the predictive values CEA was observed to
attain the best performance. Among all tests the CEA-CA 195 and CA 195
-CA 242 combinations displayed the highest sensitivities. Our results
indicate that complementation of CEA with CA 195 can significantly inc
rease the sensitivity in the serodiagnosis of gastrointestinal system
cancers. Combination of positive information is likely to lead to a mo
re accurate diagnosis and to a more efficient therapeutic response.