Prostate cancer is relatively common

A team from Wake Forest University School of Medicine in North Carolina examined a gene that controls the body's response to cancer triggers.

They found men with the disease were more likely to carry a variant which seems to increase vulnerability to environmental chemicals.

Prostate cancer affects almost 25,000 UK men a year, killing about 13,000.

Our study suggests that the genetic make-up of some men leaves them more susceptible to potential carcinogens Dr Jianfeng Xu

Although prostate cancer is the most common cancer in men, the precise cause of the disease remains is not known.

However, research suggests that a combination of genetic and environmental factors play a role.

High rates of the disease in western countries have been linked to high animal fat diets. Other risk factors include low dietary intake of the mineral selenium, and exposure to radiation or cadmium.

Researcher Dr Jianfeng Xu said: "Previous research suggests prostate cancer arises in certain individuals due to a combination of genetic and environmental factors.

"Our study suggests that the genetic make-up of some men leaves them more susceptible to potential carcinogens in the environment or hormones in the body that could trigger the disease."

Dual role

Dr Xu's team studied a gene called CYP1B1, which is thought capable both of causing cancer and preventing it.

The gene helps the body eliminate cancerous environmental chemicals - but can also activate some hormones, turning them into cancer triggers.

This could be particularly important to prostate cancer because its development is strongly dependent on hormones such as testosterone.

The US scientists found that one particular variant of the gene was found far more frequently in men who had developed prostate cancer than in those who were free from the disease.

Dr Xu said: "It's an exciting finding because we know the gene interacts with certain cancer-causing chemicals.

"Studying this more closely will bring us closer to finding out what factors in the environment or within the body may trigger the disease."

Professor Alex Markham, chief executive of Cancer Research UK, said: "It's important to find out how genetic and environmental factors combine to cause prostate cancer as, in the future, this will allow us to identify people at high-risk and advise them on ways to prevent the disease."

The research is published in the British Journal of Cancer.