No abstract

Plasma carcinoembryonic antigen (CEA) a n d serum enzyme levels of phosphohexose isomerase (PHI), gamma-glutamyl transpeptidase (y-GTP), and lactate dehydrogenase (LDH) were measured in 147 patients with malignancy. Levels were higher in patients (particularly with G.I., breast and lung cancers) than i n normals or in patients with cancer in clinical remission. Elevations of CEA and of all three enzymes i n blood were most frequent in patients with hepatic metastases. CEA elevations correlated directly with PHI levels. Seventy-eight percent of patients with metastatic G.I. cancer could be identified by CEA (>5 ng/ml) alone, as well as 38% with breast cancer a n d 85% with lung cancer; but only 17% of other cancers could be identified by CEA alone. CEA or one or more enzymes was elevated i n 64% of metastatic breast cancer patients, 92% of lung cancer and 41% of other cancers, but enzyme measurement did not increase identification of G.I. cancer over that achieved by CEA alone. These findings suggest that circulating levels of CEA, PHI, y-GTP and LDH may reflect a direct contribution from the malignant tissue and/or liver malfunction secondary to liver replacement.