Circulating Carcinoembryonic Antigen Levels and Serum Suppression of Phytohemagglutinin- Stimulated Lymphocyte DNA Synthesis: An Inverse Correlation in the Cancer Patient2

Abstract

Thirty-six patients, 23 with digestive tract cancer and 13 with breast cancer, were studied to determine the relationship between circulating carcinoembryonic antigen (CEA) levels and the suppressive activity of their sera on phytohemagglutinin-induced DNA synthesis in normal lymphocytes. Ten of 11 patients with metastases had positive serum CEA levels (>2.5 ng/cm3) , but only 2 had sera which inhibited normal lymphocyte DNA synthesis to <80% of control values. Of 25 patients with primary disease and without known metastases, 9 had positive CEA, but 14 had suppressive sera. After the primary tumor was resected, inverse changes in CEA and suppressive levels occurred. This change suggested a functional immunologic relationship between serumsuppressive activity and CEA.