Researchers find first major gene mutation associated with hereditary prostate cancer risk

After a 20-year quest to find a genetic driver for prostate cancer that strikes men at younger ages and runs in families, researchers have identified a rare, inherited mutation linked to a significantly higher risk of the disease.
A report on the discovery was led by investigators at the University of Michigan Health System and Johns Hopkins University School of Medicine. The research team found that men who inherit this mutation have a 10 to 20 times higher risk of developing prostate cancer.
While accounting for only a small fraction of all prostate cancer cases, the discovery may provide important clues about how this common cancer develops and help to identify a subset of men who might benefit from additional or earlier screening. This year, an estimated 240,000 men in the United States will be diagnosed with prostate cancer.
‘It’s what we’ve been looking for over the past 20 years,’ adds William B. Isaacs, Ph.D., professor of urology and oncology at the Johns Hopkins University School of Medicine, the study’s other senior author. ‘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.’
For this study, the researchers collaborated with John Carpten, Ph.D., at the Translational Genomics Research Institute (TGen) in Phoenix, Arizona, who used the latest technology to sequence the DNA of more than 200 genes in a human chromosome region known as 17q21-22. Cooney, working with Ethan Lange, Ph.D., of the University of North Carolina on the U-M Prostate Cancer Genetics Project, was the first to identify 17q21-22 as a region of interest.
Researchers started with samples from the youngest patients with prostate cancer in 94 families who had participated in studies at U-M and Johns Hopkins. Each of those families had multiple cases of the disease among close relatives, such as between fathers and sons or among brothers.
Members of four different families were found to have the same mutation in the HOXB13 gene, which plays an important role in the development of the prostate during the foetal stage and its function later in life. The mutation was carried by all 18 men with prostate cancer in these four families.
The researchers collaborated with Jianfeng Xu, Ph.D., and Lilly Zheng, Ph.D., at Wake Forest University to look for the same HOXB13 gene mutation among 5,100 men who had been treated for prostate cancer at either Johns Hopkins or U-M. The mutation was found in 1.4 percent—or 72 of the men. It turned out that those men were much more likely to have at least one first-degree relative, a father or brother, who also had been diagnosed. The researchers also looked for the mutation in a control group of 1,400 men without prostate cancer, and only one of those men carried the mutation. In addition, the researchers studied men who were specifically enrolled in studies of early-onset or familial prostate cancer.
‘We found that the mutation was significantly more common in men with a family history and early diagnosis compared with men diagnosed later, after age 55, without a family history. The difference was 3.1 percent versus 0.62 percent, Cooney says. University of Michigan Health System