Genetic link to prostate cancer discovered

By Dr. Ananya Mandal, MDJan 12 2012

A new study has found that men who inherit a rare genetic mutation are 10 to 20 times more likely than average to develop prostate cancer. The gene variant may help explain cases of the disease that run in families and strike men at unusually young ages.

A study of more than 5,000 men treated for prostate cancer found that 1.4% carried the defective HOXB13 gene. Men with the mutation were much more likely to have a father or brother diagnosed with the disease. It is the first major genetic variant to be associated with prostate cancer.

Professor William Isaacs, from Johns Hopkins University School of Medicine, a member of the US team, said, “It's what we've been looking for over the past 20 years. 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.” The findings are published in the New England Journal of Medicine.

Another previous study of the gene variant was reported with samples of young men with prostate cancer from 94 families with a history of the disease. Members of four different families had the same mutation in the HOXB13 gene, which plays a key role in the development and function of the prostate gland.

“We need to continue studying this variant and look at larger groups of men,” said Prof Isaacs. “Our next step will be to develop a mouse model with this mutation to see if it causes prostate cancer. Future DNA sequencing may also identify additional rare variants that contribute to prostate cancer risk in families.”

Scientists have hailed this study as a stepping stone to the development of a genetic test for detecting inherited prostate cancer. The mutation accounts for only about 1 percent of all prostate cancers. But studying it might help scientists understand the disease in general and find better treatments.

Each year around 36,000 men in the UK are diagnosed with prostate cancer and 10,000 die from the disease. More than 240,000 men are expected to be diagnosed with prostate cancer in the United States this year. Most cases are sporadic rather than inherited, and on average they are diagnosed around age 70.