Objectives: Bladder cancer represents a major health problem throughout the world, but advances in tumor biomarker development are revolutionizing how physicians diagnose the disease. We previously used an indirect immunoassay to demonstrate that the bladder cancer specific biomarker, BLCA-4, is present in urine samples from patients with bladder cancer, but not in samples from healthy individuals. In this study, a sandwich immunoassay was used to measure BLCA-4 in urine samples from patient populations with various urologic conditions and healthy individuals.
Methods: Urine was collected from healthy individuals and from patients with bladder cancer, benign urologic conditions, or prostate cancer. BLCA-4 levels were evaluated by a sandwich immunoassay using two antibodies directed against distinct epitopes on BLCA-4.
Results: Using a prospectively determined cutoff of an absorbance unit (OD) of 0.04, 67 of the 75 samples from patients with bladder cancer were positive for BLCA-4, resulting in an assay sensitivity of 89%. Also, 62 of the 65 samples from individuals without bladder cancer were negative for BLCA-4, resulting in an assay specificity of 95%.
Conclusions: The high sensitivity and specificity of the sandwich BLCA-4 immunoassay may allow for earlier detection and treatment of disease, thus greatly improving patient care.