Clinical usefulness of the novel marker BLCA-4 for the detection of bladder cancer

Purpose: Previous studies at our laboratory identified 6 bladder cancer specific nuclear matrix proteins termed BLCA-1 to 6. We recently developed an immunoassay that detects the bladder cancer specific nuclear matrix protein BLCA-4. We analyzed urine samples from patients with bladder cancer, those with spinal cord injury and normal volunteers to determine the BLCA-4 level in these 3 groups. Materials and Methods: Urine samples obtained from 51 normal controls, and 54 patients with bladder cancer and 202 with spinal cord injury were tested for BLCA-4. We evaluated the association of BLCA-4 level with tumor grade and stage, urine cytology and bladder cancer history in the nonspinal cord injured population. Similarly we compared parameters associated with BLCA-4, such as spinal cord injury duration, catheterization, history of urinary tract infection, smoking and urine culture, in spinal cord injured patients. Results: We established a normal cutoff point of 13 optical density units per μg. protein for the BLCA-4 assay. The BLCA-4 level was less than the cutoff in all 51 normal controls, while in 53 of the 55 urine samples (96.4%) of patients with bladder cancer and 38 of the 202 (19%) of spinal cord injured patients urinary BLCA-4 was greater than the cutoff. There was no correlation of any individual factors studied in these cases, including urinary tract infection and urinary BLCA- 4. Conclusions: Elevated urinary BLCA-4 levels may accurately identify bladder cancer and distinguish these patients from normal individuals. There is no correlation of urinary BLCA-4 with a history of urinary tract infection, smoking, catheterization or cystitis considered independently. Urinary BLCA-4 determination appears to have high potential as a test for screening and monitoring bladder cancer in the general population and in groups at high risk for the disease, such as those with spinal cord injury.