CIRCULATING IMMUNE-COMPLEXES (CIC) AND CARCINOEMBRYONIC ANTIGEN (CEA) AS MARKERS FOR COLORECTAL-CANCER

A total of 97 sera from 35 colorectal cancer patients was studied for circulating immune complexes (CIC) and carcinoembryonic antigen (CEA). CIC levels correlated with the clinical stages of disease; pre-treatment 17.64 +/- 8.39, 28/35 positive, p < 0.001. At the post-treatment 9.16 +/- 6.73, 8/35 positive, p non significant and at the recurrence 23.84 +/- 16.20, 22/27 positive, p < 0.001. CEA levels were concordant with the stage of disease: pre-treatment 43.35 +/- 72.00, 17/35 positive, p < 0.005; post-treatment 6.30 +/- 4.40, 6/35 positive, p non significant, and at recurrency 52.45 +/- 45.81, 16/27 positive, p < 0.001. The splitting of CIC in their constituents indicate the presence of IgG, the absence of CEA and the immune reactivity between fractions derivated from the same CIC samples in 7 out of 28 patients with disease activity (pre-treatment). Statistical analysis of CIC and CEA levels at the pre- and post-treatment revealed that both variables are independent (at the pre-treatment r = 0.09 and at the post-treatment r = 0.02. These results suggest that CIC measured by the I-125 Clq binding assay and CEA detection are useful tumor markers for monitoring colorectal cancer patients without correlation between both markers.