ABSTRACT
Carcinoembryonic antigen is a well-known tumor marker, part of a large family of closely related proteins which are expressed in several tissues, particularly epithelia of the digestive tract. Although expression of CEA does not occur in the hematopoietic system, other CEA family members are found in several types of leukocytes, especially on granulocytes. The regulation and expression of the CEA family members on leukocytes suggests a critical role for these molecules. Current data, and speculation, concerning the function of CEA members in leukocytes are presented in this chapter.
