Comparison of carcinoembryonic antigen in tissue and serum with grade and stage of colon cancer

Background: Serial plasma carcinoembryonic antigen (CEA) levels are routine ly used to defect postoperative recurrence of colon cancers. However, level s of intrinsic CEA production by individual tumors, which might be helpful for interpreting serum CEA levels, are not routinely available. Materials a nd Methods: CEA levels were determined in twenty tissue biopsy specimens of colon carcinoma and sixteen normal colonic tissue specimens from India, by immunohistochemistry (IH) and by quantitative enzyme immunoassay (EIA). Se rum samples from 62 colon cancer patients and 25 healthy blood donors were analyzed for CEA by ELA. Results: Tissue CEA levels were highest for well d ifferentiated adenocarcinomas (5.2-37 mu g/g protein) with progressively lo wer levels seen in moderately differentiated and poorly differentiated tumo rs, and in normals. The intensity of immunostaining paralleled the levels d etermined quantitatively. Mean serum CEA levels were 1.5 ng/ml for normals and 4.5 64, 23, and 102 ng/ml for Dukes'A, B, C and D stage tumors, respect ively. Conclusion: Preoperative serum CEA levels do not, in themselves, tak e into account differences in CEA production between individual tumors. Det ermination of tumor CEA content by quantitative or immunohistochemical meth ods, could be a useful adjunct for the clinical management of colon carcino ma, by improving interpretation of serum CEA levels.