Gene markers may make prostate test more accurate
Posted: Thu Dec 16, 2010 9:53 am
Gene markers may make prostate test more accurate
LONDON (Reuters) - Scientists have found a way to personalize a common prostate cancer test by looking at genetic variations, which should make it more accurate in predicting a man's risk of developing the disease.
Screening using prostate-specific antigen (PSA) blood tests is controversial at the moment because it is difficult to define normal PSA levels, so cancer is missed in some men while others get false positive results.
Improving the accuracy of the test by customizing it to individual genetic profiles should catch more men with cancer who currently slip through the net, and avoid unnecessary biopsies in those at low risk, researchers said on Wednesday.
In a study published in the journal Science Translational Medicine, an Icelandic-led team said they had discovered several DNA variations, known as single-nucleotide polymorphisms (SNPs), that affect background blood levels of PSA.
William Catalona -- a professor of urology at Northwestern University, Illinois, who developed the original PSA test and was involved in the new research -- said it was clear some men had naturally high or low levels of PSA, just as some were tall or short.
Prostate is the most common cancer in men in Western countries and kills 250,000 worldwide each year, yet it can be treated successfully if caught early.
Doctors routinely recommend a prostate biopsy for men with a PSA above a certain threshold, even though levels can rise for reasons unrelated to cancer and healthy levels vary widely.
More than a third of men with PSA levels above 10 nanograms per milliliter, for example, have no evidence of prostate cancer, and some with levels below 2.5 do.
In future, by testing for the gene variations that affect baseline PSA levels, it should be feasible to create much more accurate individual thresholds.
Decode Genetics, a Reykjavik-based biotech company whose researchers identified the SNP changes after studying the records of thousands of men, said it planned to incorporate the new markers into its prostate diagnostic tests.
"By using these markers ... we believe we have made the PSA test both more specific and more sensitive," Chief Executive Kari Stefansson said.
However, Kate Holmes, research manager at Britain's Prostate Cancer Charity, said more research on a large number of men was needed to investigate the accuracy of the new approach.
In an accompanying journal commentary, John Witte of the University of California, San Francisco, said the findings were an important step toward personalizing PSA tests and making them more useful in determining clinical options.
There could also be further genetic and other factors influencing PSA levels that might be incorporated into PSA tests in future, he added.
Source: Reuters
LONDON (Reuters) - Scientists have found a way to personalize a common prostate cancer test by looking at genetic variations, which should make it more accurate in predicting a man's risk of developing the disease.
Screening using prostate-specific antigen (PSA) blood tests is controversial at the moment because it is difficult to define normal PSA levels, so cancer is missed in some men while others get false positive results.
Improving the accuracy of the test by customizing it to individual genetic profiles should catch more men with cancer who currently slip through the net, and avoid unnecessary biopsies in those at low risk, researchers said on Wednesday.
In a study published in the journal Science Translational Medicine, an Icelandic-led team said they had discovered several DNA variations, known as single-nucleotide polymorphisms (SNPs), that affect background blood levels of PSA.
William Catalona -- a professor of urology at Northwestern University, Illinois, who developed the original PSA test and was involved in the new research -- said it was clear some men had naturally high or low levels of PSA, just as some were tall or short.
Prostate is the most common cancer in men in Western countries and kills 250,000 worldwide each year, yet it can be treated successfully if caught early.
Doctors routinely recommend a prostate biopsy for men with a PSA above a certain threshold, even though levels can rise for reasons unrelated to cancer and healthy levels vary widely.
More than a third of men with PSA levels above 10 nanograms per milliliter, for example, have no evidence of prostate cancer, and some with levels below 2.5 do.
In future, by testing for the gene variations that affect baseline PSA levels, it should be feasible to create much more accurate individual thresholds.
Decode Genetics, a Reykjavik-based biotech company whose researchers identified the SNP changes after studying the records of thousands of men, said it planned to incorporate the new markers into its prostate diagnostic tests.
"By using these markers ... we believe we have made the PSA test both more specific and more sensitive," Chief Executive Kari Stefansson said.
However, Kate Holmes, research manager at Britain's Prostate Cancer Charity, said more research on a large number of men was needed to investigate the accuracy of the new approach.
In an accompanying journal commentary, John Witte of the University of California, San Francisco, said the findings were an important step toward personalizing PSA tests and making them more useful in determining clinical options.
There could also be further genetic and other factors influencing PSA levels that might be incorporated into PSA tests in future, he added.
Source: Reuters