New Biomarkers Identify Lethal Prostate Cancer

Wednesday 11 June, 2014

MEN with prostate cancer could avoid unnecessary surgery if the findings of a preliminary study now published are validated and introduced into clinical practice.

Across Australia, 18,500i men are diagnosed with prostate cancer each year. Only a minorityii of cases lead to death but currently there is no way for doctors to accurately predict which cancers will become lethal. This results in many patients undergoing unnecessary surgery to remove the prostate.

In a paper published in Cancer Medicine three promising tissue biomarkers have been identified that separate men at higher risk of dying from prostate cancer, from those at low risk.

In the study, led by researchers at Cancer Council Victoria's Cancer Epidemiology Centre and TissuPath Specialist Pathology, the expression of six protein biomarkers was assessed on the diagnostic tissue of men with prostate cancer.

The researchers found if the "MUC1" or "p53" proteins were present in the tumour biopsies men were twice as likely to die of prostate cancer as those without the biomarkers. In addition, the research team found a third biomarker "AZGP1" that, if present, reduces a man's risk of dying from prostate cancer threefold.

The finding on "p53" validates an earlier study. Cancer Council's David Hill Research Fellow and study co-author Liesel FitzGerald said if the findings for "MUC1" and "AZGP1" were also validated in an independent, larger-scale study then doctors may one day be able to use all three biomarkers to accurately predict which tumours required aggressive treatment.

"Only a minority of prostate cancer diagnoses lead to death but due to a lack of markers of aggressive disease, many non-lethal cancers are still treated aggressively," Dr FitzGerald said.

"If this preliminary study is validated this research can inform clinical practice so both doctors and patients understand whether their tumour is likely to progress and make more informed decisions on how best to treat it."

TissuPath Specialist Pathology Director of Research and Development Professor John Mills said the findings could benefit thousands of men across the country being diagnosed with prostate cancer - the most commonly diagnosed cancer among Australian men.

"For a cancer that is so frequently diagnosed by needle biopsies, we actually know very little about the whole of the tumours because they are buried in the body. Using these biomarkers sheds more light on how the tumours are likely to behave. We are currently investigating further protein biomarkers which we think will further improve our ability to predict the behaviour of prostate cancers."

Professor Mills said an advantage of this study was that it used a technique known as immunohistochemistry or "IHC", which is simple, inexpensive, and available in almost all pathology practices making it easy for clinical practice to adopt.

Prostate cancer now accounts for one in every three new cases of cancer diagnosed in Victorian men. Incidence rates rose steeply between 1987 and 1995 largely due to the introduction of the Prostate Specific Antigen test which detects early asymptomatic cancers. Prostate cancer is the second ranking cause of cancer death for meniii.

i 18560 new cases of prostate cancer in Australia in 2010 according to Cancer in Australia: An Overview 2012 by the Australian Institute of Health and Welfare. In Victoria there were 4764 new cases of prostate cancer in 2012, which accounts for 30 per cent of cancers for men according to Cancer in Victoria: Statistics and Trends 2012 by the Victorian Cancer Registry.
ii 92 per cent of men with prostate cancer will survive five years after diagnosis in Australia according to Cancer in Australia: An Overview 2012.
iii In Victoria in 2012, 790 men died of the disease according to Cancer in Victoria: Statistics and Trends 2012. In Australia in 2010, 3235 died of the disease according to Cancer in Australia: An Overview 2012.