Researchers have identified nine new genetic variants that may increase the risk of developing prostate cancer in Black patients, according to a novel study published by Chen et al in European Urology. The investigators also found that genetic differences may help determine which patients are most likely to develop aggressive types of the disease.
Background
Prostate cancer may take a greater toll on Black patients than on individuals of other races. In the United States, one in six Black patients are predicted to get prostate cancer in their lifetime—compared with one in eight patients overall. Black patients may also be more than twice as likely to die from the disease.
While past studies have identified nearly 270 genetic variants linked to a greater risk of developing prostate cancer, researchers have yet to find a clear explanation for the disproportionate risk among Black patients. Genetic research thus far has also failed to predict which patients face a high risk for aggressive prostate cancer and which will develop less deadly forms of the disease. New discoveries from the current study—one of the largest studies of prostate cancer in Black patients—are now addressing those long unanswered questions.
“The ability to differentiate between the risk for aggressive and nonaggressive forms of the disease is of critical importance,” explained senior study author Christopher Haiman, ScD, Professor of Population and Public Health Sciences and Director of the Center for Genetic Epidemiology at the University of Southern California, Los Angeles (USC) Keck School of Medicine; as well as AFLAC Chair in Cancer Research and Co-Leader of the Cancer Epidemiology program at the USC Norris Comprehensive Cancer Center. “Until now, risk scores haven’t been able to do that,” he added.
Study Methods and Results
In the new study, the researchers included 19,378 patients with prostate cancer and 61,620 healthy controls from 10 genome-wide association studies—representing virtually all of the existing data on genetic risk for prostate cancer in Black patients. After conducting a meta-analysis, they found nine previously undiscovered genetic variants that increased the risk of prostate cancer among this patient population. Seven of those variants—including one in the 8q24 region—were found to be primarily or even exclusively present in Black patients, underscoring the importance of including diverse populations in large-scale genetic studies.
“This particular variant is influencing the risk of aggressive disease in this population,” emphasized Dr. Haiman.
The researchers also detected some of the same patterns seen in previous studies, including that genetic influence may play a bigger role in cancer risk for younger patients compared with their older counterparts.
Better Screenings to Assess Prostate Cancer Risk
Additionally, the novel findings can be used to refine polygenic risk scores—tools that assess an individual’s risk for a condition based on the combined influence of multiple genetic factors. More accurate polygenic risk scores for Black patients could help identify those who are at high risk early in their disease development.
“Prostate cancer survival is significantly lower among [patients] diagnosed with aggressive disease,” said lead study author Fei Chen, ScM, PhD, Assistant Professor of Clinical Population and Public Health Sciences at the Keck School of Medicine at USC. “Our findings suggest that these polygenic risk scores could be useful for identifying [patients] who may benefit from earlier and more frequent screenings,” she said.
They may also help patients understand their cancer risk and decide how early and often to get screened.
Conclusions
Through the RESPOND initiative—a collaboration between the National Institutes of Health and the Prostate Cancer Foundation—the researchers are further studying how social determinants of health, access to care, and other factors may affect prostate cancer recurrence, progression, and survival rates among Black patients. One of their long-term goals is to develop a widely available genetic screening test that can help patients of all ages assess their risk levels.
“Through the Robert F. Smith–[Prostate Cancer Foundation] Special Challenge Award for the Smith Polygenic Risk Test, the Prostate Cancer Foundation is proud to invest in the critical work of the RESPOND [initiative] to understand and address the reasons why [Black patients] disproportionally experience aggressive prostate cancer, and ultimately advance our shared mission to end death and suffering from this disease,” expressed Howard R. Soule, PhD, Executive Vice President and Chief Science Officer of the Prostate Cancer Foundation.
“The vast majority of studies to date have been conducted in populations of European ancestry, which creates a huge bias in our understanding of genetic risk for disease,” Dr. Haiman stressed.
The researchers noted that evidence of risk factors specific to this population points to the importance of continuing to collect data from diverse groups—including Black patients as well as Asian and Hispanic patients. They also concluded that polygenic risk scores have potential clinical utility to differentiate between the risk of developing aggressive and nonaggressive prostate cancer in Black patients.
Disclosure: The research in this study was supported by the National Cancer Institute, the Prostate Cancer Foundation, and the Million Veteran Program. For full disclosures of the study authors, visit sciencedirect.com.
