Evaluation of CA19-9 as a tumor marker in urothelial malignancy

Objective: Carbohydrate antigen 19-9 (CA19-9) is known to be a marker with a high positive rate in pancreatic cancer. There are limited data on the use of CA19-9 as a tumor marker in bladder carcinoma. We tested the expression of CA19-9 in transitional cell carcinoma (TCC) cell lines and bladder cancer patients to determine its usefulness in clinical applications. Material and Methods: The expression of CA19-9 was determined in six TCC cell lines and 42 bladder carcinoma tissues using two approaches: immunohistochemistry and enzyme immunoassay (EIA) analysis. EIA was used for testing CA19-9 levels in spent medium of cultured TCC cells and the urine of bladder tumor patients. Results: The CA19-9 value was low in spent media of the MGH-U1, MGH-U1R and MGH-U3 cell lines, but high in that of the MGH-U4 cell line, which was derived from atypia urothelial cells. Immunostaining revealed positive cytoplasmic CA19-9 reactivity in MGH-U4 cells, while negative reactivity was found in high-grade MGH-U1 and MGH-U1R cells, both of which were derived from a stage B, grade 3 TCC. High incidences of negative CA19-9 staining were found in high-grade and invasive tumor tissues: 69.6% (16/23) and 70.8% (17/24), respectively. The sensitivity and specificity of urinary CA19-9 for detecting tumor recurrence were 83.3% and 50.8%, respectively. However, urinary tract infection also resulted in a high false-positive rate. Conclusion: CA19-9 is promising for use as a biomarker for the detection and monitoring of low-grade and low-stage bladder cancer, with the proviso that patients to be tested should be free of infection.