Rapid and quantitative detection of human septin family Bradeion as a practical diagnostic method of colorectal and urologic cancers

Abstract

Background: Malignant tumor progression is a complex and multi-gene event which can not be easily detected or predicted. The detection of malignant cells using marker genes is hampered by the fact that these markers are only expressed by certain malignancies or lack sensitivity and/or specificity. We have reported a human septin family gene Bradeion, which shows strong cancer-specific expression in colorectal and urologic cancers as a result of carcinogenesis.

Material/methods: Diagnostic efficacy and validity of Bradeion gene expression were tested by two independent systems, one is a protein detection method using monoclonal antibody based immuno-chromatographic membrane strip tests (a nitrocellulose test strip assay), and another is a gene expression detection method, quantitative RT-PCR. The technology has been established using Bradeion fusion proteins, in vitro cultivated human cancer cell lines, and also patients' test samples with controls.

Results: Bradeion test strip by combination with two monoclonal antibodies are valid for the detection of 1 ng/ml Bradeion, and successfully applied for patient urine samples with no false-positive results. Positive detection rates were over 70% of the patient urine samples so far tested (prostate cancer, renal cell carcinoma, and bladder cancer) in 15 to 30 minutes. Quantitative RT-PCR resulted in significantly high copy numbers of 0.4-3.0-3.0 x 10(5) per microg total RNA in patients' tissue samples, whereas those from normal tissue or other cancers found negative.

Conclusions: The present study introduces the practical diagnostic methods using a disease-specific molecular marker, which provides safe, economical, and rapid clinical screening of cancer.