CEACAM5 and colon carcinoma: A CEA-negative subclone from the human colon carcinoma cell line CO115 was transfected either with CEA-cDNA truncated at its 3′ end by the deletion of 78 base pairs leading to the synthesis of a secreted form of CEA or with a full-length CEA-cDNA leading to the synthesis of the entire CEA molecule linked to the cell surface by a GPI anchor.