Serum lipid-bound sialic acid in lung cancer patients

Serum lipid-bound sialic acid (LSA) assay was evaluated for differential diagnosis between benign and malignant pulmonary disease. Mean serum LSA for normal controls was 13.7±3.7 mg/dl and the upper limit of the normal value was set at 19.8 mg/dl (95% confidence limit, one side). The specificity was 97.1% (95% confidence interval was 93.8%, 100.0%). The mean for benign pulmonary disease was 17.1±5.1 mg/dl, the specificity was 89.1% (95% confidence interval was 80.9%, 97.3%), and the sensitivity was 10.9%. The mean for malignant pulmonary disease was 27.1±7.9 mg/dl, and the sensitivity was 93.3% (95% confidence interval was 88.5%, 98.1%). The serum LSA levels for different malignant pulmonary diseases were different between small cell carcinoma and adenocarcinoma. The results indicate that serum LSA assay might be used as tumor marker to differentiate lung cancer from normal subjects or benign lung disease.