Plasma lipid-bound sialic acid and carcinoembryonic antigen in cancer patients.

We evaluated lipid-bound sialic acid as a "marker" in cancer patients and assessed the individual and combined value of lipid-bound sialic acid and carcinoembryonic antigen determinations in these patients. Plasma was sampled from 62 normal subjects and 125 cancer patients. Lipid-bound sialic acid was determined by the resorcinol method after total lipid extraction and isolation of the sialolipid fraction from plasma. Neither marker was increased in many breast cancer patients. Carcinoembryonic antigen was increased more commonly and to a greater degree in colon cancer patients and seems to be the preferred marker. Both markers were increased in lung cancer patients and their combined evaluation improved the rate of detection. Lipid-bound sialic acid was increased in more patients with leukemias, lymphomas, Hodgkin's disease, and melanomas, suggesting that it may be a useful biochemical marker in these types of cancer.