New Prostate Cancer Test Could Be 90 Per Cent Accurate

Article Date: 29 Sep 201

According to early findings of a pilot study presented at a conference in the US this week, the controversy surrounding prostate cancer screening could be about to change: a UK company has developed a panel of biomarkers that appears to distinguish samples of prostate cancer from samples of benign prostate disease and healthy prostate tissue 90 per cent of the time, considerably higher than current diagnostic tests.

Oxford Gene Technology (OGT) said in their pilot study involving 73 prostate cancer and 60 control samples, they identified a set of biomarkers that differentiated prostate cancer from control samples with both "sensitivity and specificity above 90 per cent".

The company's Vice President of Biomarker Discovery, Dr John Anson, presented the findings at the Fourth American Association for Cancer Research International Conference: Molecular Diagnostics in Cancer Therapeutic Development, that is taking place from 27-30 September in Denver.

For the pilot study, OGT said in a statement that they tested their own newly developed "functional protein" microarray platform called the Sense Proteomic, which uses over a thousand "correctly folded proteins to detect autoantibodies in prostate cancer serum samples".

Autoantibodies are antibodies that the immune system produces to attack the body's own proteins, for instance as in lupus and type 1 diabetes. But cancer can also cause the immune system to create autoantibodies because it changes normal proteins.

Anson told Reuters in a telephone interview that their test looks for higher levels of these autoantibodies as early signs of disease. He also said the test could potentially be used to screen for other cancers.

In the statement, he said CGT were very happy with their initial findings: so much so that they have now set up a follow-on clinical study using 1,800 samples to develop and validate the panel of biomarkers.

CGT said the new trial will use 400 prostate cancer samples, an equal number of matched normal samples, about 150 samples of other cancers, and several hundred samples from patients with other prostate diseases. 

The current most effective test for prostate cancer, the PSA test (short for prostate specific antigen) only uses one biomarker, which can lead to false positives and trigger unnecessary biopsies and treatments because non-cancer diseases of the prostate can also raise PSA levels. 

So by including non-cancer diseases of the prostate in the bigger trial OGT expect to show that their new biomarker panel can tell the difference between prostate cancer and these other diseases.

OGT said the results of the new trial should be out in the first half of 2011. Anson said based on the pilot study results and the bigger trial, they are already looking at opportunities to partner with diagnostic and pharmaceutical companies for the development of a diagnostic test.

"We are also exploring the extensive potential of our Sense Proteomic functional protein array technology for improving the diagnosis of other cancers and autoimmune diseases," he added.

If the bigger study proves successful, the company expects the test to be available for clinical use in about 5 years, reported Reuters.

Over quarter of a million people die every year worldwide because of prostate cancer. The disease is the second most common cause of cancer death among men in the US, where 32,000 are estimated to die from it this year.

The current PSA test only has a specificity of less than 50 per cent, causing many unnecessary procedures as well as much uncertainty, stress and worry for the patients concerned. Having a biopsy also carries risks, as do other surgical procedures and radiotherapy.

OGT says it has also validated its functional protein microarray technology in studies in systemic lupus erythematosus (SLE) and non-small cell lung cancer. 

The company says the technology could also be used to monitor immune system reactions to drugs in clinical trials, allowing drug companies to spot off-target effects of new therapies and to develop companion diagnostics.

Sources: OGT, Reuters.

Written by: Catharine Paddock, PhD