Abstract
Prostate cancer treatment has risk associated with patients' being overdiagnosed leading to an overtreatment epidemic. In the United States 1 in 9 males are diagnosed with prostate cancer with approximately 10% of these patients having aggressive forms usually requiring surgery. To diagnose these patients, physicians most often rely on the Prostate Specific Antigen (PSA) blood test and the digital rectal exam. PSA is currently the only biomarker approved for prostate cancer diagnostics, but cannot discern cancer from other prostate conditions, such as Benign Prostatic Hyperplasia (BPH) or Prostatitis. Most importantly, PSA cannot identify the aggressive forms of prostate cancer. These inaccuracies lead to unnecessary treatments including surgery of indolent prostate cancer patients that adversely affect the patients' quality of life. Measurements of small panels of molecular biomarkers in serum holds tremendous potential for cancer diagnostics and personalized therapy. We are evaluating a new protein panel for prostate cancer including PSA, CD-14, ERG, GOLM-1, PEDF-1, IGF-1, VEGF-D and IGFBP-3 that may be indicative of prostate cancer or cancer progression. We designed a microfluidic immunoarray that features miniaturisation, low sample volume, sensitivity adjustable to the sample characteristics, rapid analysis, and low reagent consumption. A protocol was developed for the simultaneous assay of this 8-protein panel in serum that features online capture and detection with a semi-automated multiple protein immunoarray. A nanostructured sensor array with bound capture antibody in the microfluidic device captures the biomarker proteins from the sample, and a sandwich immunoassay is completed following a concurrent injection of target protein standards or sample, biotinylated secondary antibody and polymerized horseradish peroxidase into the detection chamber. Ultra-low limits of detection (LOD) in the sub fg ml-1 range were achieved for the proteins in the panel. Using this strategy, 8-16 proteins can be detected simultaneously within 30 minutes. Measurements of the biomarker panel tested with prostate cancer patient samples and statistical analyses to assess diagnostic utility will be described.