a study of lipid- and protein- bound sialic acids for the diagnosis of bladder cancer and their relationships with the severity of malignancy

background: the gold standard for detection of bladder cancer is cystoscopy, which is an invasive and complicated procedure. our study was conducted to find a tumor marker with high specificity, sensitivity, and accuracy for the diagnosis of bladder cancer. methods: serum samples were collected from 58 bladder cancer patients and 60 healthy control subjects. levels of lipid-bound sialic acid (lbsa), and protein-bound sialic acid (pbsa) were measured spectrophotometrically by aminoff’s method. results: mean levels of both markers were found to be significantly higher in the patients than the healthy controls. positive correlations were observed between serum levels of lipid- (r=0.283, p<0.05) and protein- bound (r=0.56, p<0.05) sialic acids and the grade of malignancy. to differentiate patients with bladder tumors from healthy controls, cut-offpoints were determined for each of the two parameters based on receiver operating characteristic (roc) curve analysis (lbsa=21.25 mg/dl, pbsa=6.15 mg/dl). the data showed good sensitivities (lbsa=89%, pbsa=79%), specificities (lbsa=70%, pbsa=70%) and accuracies (lbsa=83%, pbsa=81%) for both markers. conclusion: measuring serum lbsa and pbsa by this simple, reproducible, noninvasive, and inexpensive method can accurately discriminate cancer patients from healthy individuals.