Serum free and bound sialic acid and alpha-1-acid glycoprotein in patients with laryngeal cancer.

Serum specimens from 35 patients with laryngeal cancer (10 at stage II; 12 at stage III; 1.3 at stage IV) were obtained before therapy was initiated. Concentrations of bound sialic acid (BSA), free sialic acid (FSA), and alpha-1-acid glycoprotein (AAG) were compared to those in serum specimens from 34 healthy controls. The mean levels of serum BSA and AAG were significantly increased in the laryngeal cancer patients versus the controls; there was no significant difference in serum FSA levels between the patients and controls. Mean serum BSA and AAG levels were lowest in the control group and highest in the stage IV patients. As the stage of the cancer advanced, progressively higher levels of serum BSA and AAG were observed. The results indicate that serum BSA and AAG, but not FSA, show correlation with the stage of laryngeal carcinoma.