Prostate cancer is three times more likely to affect black men in England than white men, a study has shown.
And black men also tend to be diagnosed five years younger, although researchers at the University of Bristol found no link between the result of the study and poorer access to health care.
They said the differences in prevalence could not be explained by differences in the tests, screening or information that black or white men had about the condition.
Reporting in the the British Journal of Cancer, scientists said black men were more likely to be referred to hospital for further investigation by their GP.
The study was looking at whether more black men got prostate cancer or just whether they were more likely to be diagnosed.
Study leader Dr Chris Metcalfe told the BBC: "One of the possibilities based on anecdote was that black men may delay presentation - so the cancer gets to a later stage.
"If anything the evidence showed black men were presenting sooner."
Dr Joanna Peak, science information officer at Cancer Research UK, said: "The study indicates that there is a true biological difference between ethnic groups and this knowledge could potentially lead to improved care for men at higher risk of developing prostate cancer."