Evaluation of N-acetylneuraminic acid, carcinoembryonic antigen, and alpha-fetoprotein as markers for advanced carcinoma.

Sialic acid (N-acetylneuraminic acid, NANA), carcinoembryonic antigen (CEA), and alpha-fetoprotein (AFP) were measured in a group of patients with advanced carcinoma (primarily colorectal). The percent change of NANA was less than that with CEA, and more reliably separated patients with stable disease from those with tumor regression or progression. AFP was a good predictor of clinical course in the few patients in which it was measured.