Platelet sialic acid in malignant disease.

n-Acetylneuraminic acid (NANA) was measured in the platelets and serum of normal subjects, patients with malignant disease, and patients with acute myocardial infarction. The malignant disease group had a mean platelet NANA 24% below normal and a serum NANA 68% above normal. Both results were highly significant. Samples from patients with acute myocardial infarction showed slightly reduced platelet NANA and slightly raised serum NANA, neither change being significant. There was no correlation between platelet and serum NANA in the neoplastic group.