Postsurgical Immunoassay Predicts Prostate Cancer Recurrence

A novel test could reliably detect early increases in prostate specific antigen levels, a biomarker commonly used to measure the recurrence of prostate cancer.

A simple blood test can measure PSA in men who have undergone prostate cancer-treating surgery with unprecedented sensitivity and at much lower levels than standard PSA tests because it can selectively capture and measure individual PSA molecules.

Single Molecule Array (SiMoA) technology is based upon the isolation of individual immunocomplexes on beads using standard enzyme linked immunosorbent assay (ELISA) reagents. The AccuPSA test uses beads with or without labeled immunocomplexes are loaded into arrays containing femtoliter-sized wells and the arrays are sealed in the presence of the enzyme substrate and fluorescently imaged. Fluorescent product molecules of the enzyme-substrate reaction are confined in a 50 fL volume, giving rise to a local high concentration of product within a matter of a few seconds that can be easily detected using a low cost imaging system.

The AccuPSA test is manufactured by Quanterix Corporation, (Cambridge, MA, USA). To demonstrate the assay's clinical potential, PSA was measured in serum from 60 men who had undergone radical prostatectomy for prostate cancer. For the majority of these patients PSA is initially reported as undetectable following surgery, but may be present at very low levels that predict the likelihood of disease recurrence. The test was so sensitive that it was able to measure residual PSA levels in all samples tested. The PSA levels had been reported to be undetectable in these samples by standard tests, highlighting the sensitivity and precision of the SiMoA technology. The findings were presented at the Fourth American Association for Cancer Research's International Conference on Molecular Diagnostics in Cancer Therapeutic Development that was held during September 23 – 27, 2010, in Denver (CO, USA).

David Wilson, Ph.D., senior director at Quanterix Corporation, said, "AccuPSA has the potential to eliminate unnecessary treatments and enable earlier detection of recurrence, which may lead to earlier treatment, better outcomes and have a positive impact on health care costs."

Related Links:
Quanterix Corporation
American Association for Cancer Research