Inexpensive Test Bests PSA for Prostate Cancer Screening

Qun Huo (University of Central Florida)

3 April 2015. An inexpensive lab test using gold nanoparticles is shown in a new study to be more sensitive and specific in screening for prostate cancer than the standard prostate-specific antigen or PSA screen. A team from University of Central Florida in Orlando, led by materials science and medical professor Qun Huo,  published its findings last month in the journal ACS Applied Materials and Interfaces (paid subscription required).

PSA tests are a widely used screening procedure for prostate cancer. The test measures the amount of the prostate-specific antigen protein in the blood, where elevated levels of PSA can indicate malignant prostate tissue. But PSA tests are not foolproof, and elevated levels can also indicate non-cancerous conditions such as an enlarged prostate. Medical organizations remain divided on recommending the test, particularly for older men, over the age of 75.

Huo and colleagues sought a more reliable and sensitive measure screening method for prostate cancer. Like the PSA, the test devised by researchers measures the immune response generated by a potential malignancy, but instead measures the amount of human immunoglobulin G, a type of antibody produced by the immune system.

The Central Florida test uses a few drops of blood from a pin prick, which are mixed with gold nanoparticles, considered highly efficient in absorbing and scattering light. The mixture of blood and gold nanoparticles are then analyzed for the amount of light absorbed and scattered, in a technique known as nanoparticle-enabled dynamic light scattering assay.

The researchers ran their test with two pilot blood serum samples, collected from Florida Hospital Cancer Institute in Orlando and Prostate Cancer Biorespository Network. The pilot tests showed the gold nanoparticle screening method returned results with a specificity of 90 to 95 percent, and sensitivity of 50 percent. Sensitivity indicates true positive responses, while specificity indicates true negative responses. On both measures, the results are higher than PSA screens, which have a 20 percent sensitivity.

In addition to returning more sensitive and specific results, the test designed by Huo and colleagues is likely less expensive than PSA screening. A small bottle of gold nanoparticles mixed in a suspension with water costs about $250 and provides enough for 2,500 tests.

Huo co-founded a start-up company, Nano Discovery Inc., to commercialize her research. The company, located in a university incubator in Orlando, is planning to develop a device for diagnostic screening and research.

“What’s different and unique about our technique is it’s a very simple process, and the material required for the test is less than $1,” says Huo in a university statement. “And because it’s low-cost, we’re hoping most people can have this test in their doctor’s office. If we can catch this cancer in its early stages, the impact is going to be big.”

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