Background: The secretion of carcinoembryonic antigen (CEA) by many colorectal tumors is associated with a worse prognosis and a greater likelihood of metastases. The exact biologic function of CEA is not known. In the literature, it has been postulated CEA may be a tumorigenicity-enhancing factor.
Methods: Ten different human colonic adenocarcinoma cell lines (RW-7213, RW-2982, LS174T, SW1116, RW-5928, DLD-2, SW-48, DLD-1, SW-480, and HCT-8) with a wide range of CEA production (from undetectable to 5200 ng/ml in culture medium) were injected into the spleens of groups of nude mice as a model for experimental hepatic metastasis.
Results: There was a wide range in local tumorigenicity in the spleen (from 0-90%) and in liver metastases (from 0-70%). The capacity to grow in both liver and spleen was associated with CEA production. The four cell lines that secreted the highest amounts of CEA produced the highest tumorigenicity in the spleen (67-90%) with frequent liver colonization (25-70%). The two cell lines that secreted no detectable CEA produced neither splenic tumors nor hepatic colonies. Low-level CEA production was associated with intermediate and more variable tumorigenicity.
Conclusions: There was an association between CEA secretion and the ability of 10 different colorectal cell lines to grow in nude mouse spleen and liver models.