Ethnicity Matters in Research: A Case Study in Prostate Cancer

By Angela Liu and Shirley Wu

Nearly one in six men in the United States develops prostate cancer. This sobering statistic has spurred tremendous advances in research over the years, such that prostate cancer is now one of the most treatable and survivable cancers. But there is still much we don’t know about prostate cancer and the factors leading to its development. These factors include non-genetic factors such as diet and lifestyle, but also include genetic factors — variants of DNA that differ between individuals and are associated with susceptibility to the disease.

With new ways of probing the human genome, our knowledge of the genetic factors contributing to risk for prostate cancer is growing. Researchers have identified dozens of genetic associations over the last five years related to prostate cancer. But is the current pace of research enough?

We would say no. Consider this: rates of prostate cancer in African American men are 1.5 to 3 times higher than for men with non-African ancestry, and African Americans have a  two-fold higher mortality rate from the disease compared to European Americans. Non-genetic factors surely play a role in these differences, and chances are that genetic factors contribute, too. But nearly all of the genetic research in prostate cancer has been in populations of European descent. Our knowledge of prostate cancer genetics in African ancestry individuals specifically — a group especially affected by the disease — is progressing much too slowly.

The few studies in African Americans have mostly been unable to confirm genetic associations identified in European populations, suggesting that different genetic factors influence risk in these two groups. A large study published recently in PLoS Genetics showed systematically that genetic risk variants identified in Europeans are not representative for African Americans. Looking at more than 10,000 African American men, these researchers found that only half of the European risk variants were associated with prostate cancer in their study group. Even when the same region of the genome was associated with prostate cancer in both populations, the exact location or variant often differed.

As the PLoS study illustrates, findings from one population can’t simply be applied to other populations, emphasizing the need for more research in different populations. A recent study published in Nature Genetics, identifying a new risk variant associated with prostate cancer in African Americans, is an important step in the right direction, but even more studies are needed. The especially high rate of prostate cancer in African American men illustrates how crucial it is to deepen our understanding of prostate cancer specifically in African Americans. And changing research generally to focus on more diverse groups has the potential to improve how we treat and prevent disease in all populations.

At 23andMe, we recognize that some of the biggest impacts in healthcare will come from changing how research is done. We recognize areas where traditional research models are failing and are committed to engaging patients, scientists, and the every day consumer to make a difference. 23andMe’s innovative research platform has already transformed research in  Parkinson’s disease, and it can do the same to accelerate research in diverse populations. Keep on the lookout for upcoming projects from 23andMe that focus research where it is needed most!