FRIDAY, Oct. 23 (HealthDay News) -- A new test for prostate-specific antigen (PSA) levels is considerably more sensitive than commercial assays and allows better monitoring for recurrence after prostatectomy for early-stage prostate cancer, according to a study published online Oct. 19 in the Proceedings of the National Academy of Sciences.
C. Shad Thaxton, M.D., of Northwestern University Feinberg School of Medicine in Chicago, and colleagues developed an ultrasensitive, automated gold nanoparticle bio-barcode PSA assay. They compared the assay with commercial assays to test serum samples from 18 men who had undergone radical prostatectomy for clinically localized prostate cancer.
The researchers found that the assay could detect 330 fg/mL of PSA and was about 300 times more sensitive than commercial assays. All patients had measurable levels of PSA after surgery with the barcode assay. Men who consistently had low PSA levels over time after surgery did not have recurrence, while the majority of men whose PSA levels rose with time after surgery had their cancer recur.
"In conclusion, we have synthesized and characterized a new PSA gold nanoparticle bio-barcode assay probe and demonstrated that it can be used in a novel automated format," the authors write. "This increase in sensitivity offers the opportunity to monitor existing biomarkers at levels not possible with conventional assays."
Several authors reported financial relationships with Nanosphere Inc., which licensed the bio-barcode assay from Northwestern University.
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