Scientists have discovered genetic mutations that may help explain why black men have a greater risk of developing prostate cancer than those of other ethnicities. The findings may lead to a test to identify those at greatest risk of the development of the disease, improving survival rates.
Prostate cancer is the most common cancer among British men, with around 52,300 new cases and 12,000 deaths recorded in the UK each year. Black men are twice as likely to be diagnosed and 2.5 times more likely to die from the disease compared to white men.
The reason for this difference is unclear, but it is thought that different levels of a protein called the androgen receptor are involved. Male hormones like testosterone bind to it, sending a signal to cancer cells telling them to keep growing and dividing. But while previous studies have suggested that black men have higher levels of androgen receptor, until now no one really understood why.
A key problem has been that the genetic databases researchers use to search for sequences that might help explain such differences are largely based on DNA from white men. “There hasn’t really been a lot of information about the different frequencies of mutations across populations to explain why black men are more likely to develop prostate cancer,” says Dr Greg Brooke, a senior lecturer at the University of Essex, who led the research co-led. .
To overcome this problem, Dr Antonio Marco, also at the University of Essex, developed an approach that looks for differences in the regulatory regions of genes, while taking into account recently collected information about differences in human populations.
They used this tool to analyze DNA from more than 75,000 people from diverse populations worldwide, looking for regulatory regions that could explain why black men produce higher levels of androgen receptors.
The research, which has not yet been published, identified mutations in three regions of DNA that control androgen receptor levels. “These specific changes to the genetic code [mutations] are frequently found in men of African descent while being virtually absent in men of European descent,” said Marco.
They also identified hundreds of other mutations that differ between populations and may affect men’s risk of prostate cancer. These discoveries could eventually lead to a genetic test that could predict which subset of men are most likely to develop the disease. “Such tests could change the management of this disease in a similar way that mammograms have for breast cancer,” Brooke said.
Dr Naomi Elster, the director of communications at Prostaat Cancer Research, which funded the study, said: “For far too long people have known about the difference in prostate cancer between black and white men and not done enough about it. This important research is changing that and giving us some much-needed answers about why black men are at greater risk.
“We hope this will lead the way to us being able to identify black individuals who should be tested more often and may need different treatments, helping to narrow the gap in survival.”
