16 January 2012
ByAppeared in BioNews 640
A rare gene variant that could increase the risk of prostate cancer has been identified by researchers in the USA. Although the variant accounts for only a small fraction of all prostate cancers, the study found it was more common in men with an inherited form of the cancer and those who are diagnosed before the age of 55. The researchers say the findings, which are yet to be confirmed in larger studies, could be used to screen men from families with a history of hereditary prostate cancer.
Professor William Isaacs, from Johns Hopkins University School of Medicine, who led the research, said: 'It's long been clear that prostate cancer can run in families, but pinpointing the underlying genetic basis has been challenging and previous studies have provided inconsistent results. It's what we've been looking for over the past 20 years'.
So far, nearly 50 gene variations have been linked to prostate cancer, but each one is believed to have only a small influence on the disease. But the recent finding - a variant on the gene - HOXB13 - may allow researchers in future to develop tests that can identify those at 'high risk' of developing the condition.
Professor Ros Eeles, a geneticist from at the Institute of Cancer Research and the Royal Marsden NHS hospital in the UK, said the finding is in line with current genetic understanding of prostate cancer. 'We think that prostate cancer genetics is a mixture of 'lower risk' gene variants that are common in the population, and rarer 'higher risk' variants', she said.
The researchers, based at the Johns Hopkins University School of Medicine and the University of Michigan, examined DNA samples taken from 94 unrelated patients with prostate cancer in families with multiple cases of the disease among the men's immediate relatives.
The researchers used DNA sequencing to analyse more than 200 genes near chromosome 17, which had previously been linked to inherited or early-onset prostate cancer. The variant was discovered in four families with a history of prostate cancer and it was found that 18 of the men with the disease all had the same fault in the gene HOXB13.
To investigate their findings further, the researchers studied samples from nearly 5,100 unrelated prostate cancer patients. They found that the HOXB13 mutation was present in 1.4 percent of these patients. By contrast, they only found HOX13B faults in 0.1 percent of healthy men.
Professor Kathleen Cooney, a researcher on the team at the University of Michigan, said although the variation may be linked to only a small proportion of tumours, 'we're optimistic that this could be important for patients and families and this might give an opportunity for early detection and treatment'.
Speaking to Nature News, Dr Elaine Ostrander, a geneticist at the National Human Genome Research Institute in Maryland, USA, who was not involved in the study, commented: 'What we need to do next is determine if you have a mutation in this gene how likely are you to get prostate cancer and at what age'.
Prostate cancer is the most common cancer in men in the UK, with a 100 men being diagnosed every day. 250,000 men are currently living with the disease. The study was published in the New England Journal of Medicine.