Combined measurement and significance of lipid-bound sialic acid and carcinoembryonic antigen in detection of human cancer.

We evaluated the clinical usefulness of lipid-bound sialic acid (LSA) as a "tumor marker" and assessed individual and carcinoembryonic antigen (CEA) in cancer patients. Serum LSA and CEA concentrations were measured by the resorcinol method after total lipid extraction and isolation of the sialolipid fraction, and by Abbott enzyme immunoassay procedures, respectively. Results indicate that the frequency of elevation and mean LSA values were highest in patients with lung cancer (318 mg/liter), intermediate in miscellaneous (210 mg/liter) and colorectal cancers (200 mg/liter), and lowest in breast cancer (175 mg/liter); while mean CEA values were highest in colorectal cancer (162.5 micrograms/liter), followed by lung (33.8 micrograms/liter), miscellaneous (30.3 micrograms/liter), and breast cancers (11.6 micrograms/liter). Statistically, LSA and CEA values for cancer patients were significantly (P less than 0.001) higher than for normal subjects. The combined measurement of LSA and CEA in serum provides better detection potential for cancer patients than either of the two markers alone.