Black men in the United States are at a greater risk of prostate cancer than men of other races, with one in six Black men likely to develop the disease in their lifetime compared to one in eight men overall.
Furthermore, Black men are over twice as likely to die from prostate cancer, as per a press release from the Keck School of Medicine of USC.
Why are Black men disproportionately affected?
Despite past studies had identified almost 270 genetic variants linked to prostate cancer risk, it is still unclear why men of African ancestry are disproportionately affected.
Moreover, genetic research has failed to predict which men are at risk of aggressive prostate cancer, as opposed to those who may develop less severe forms of the disease.
However, new research from the Keck School of Medicine of USC has made significant strides in addressing these unanswered questions. The study, which is the largest-ever study of prostate cancer in men of African descent, includes genome-wide association study data from over 80,000 men.
Researchers found nine new genetic risk factors for prostate cancer, seven of which are found predominantly or exclusively in men of African ancestry. The research also established that genetic differences can determine which men are most likely to develop aggressive prostate cancer.
Christopher Haiman, ScD, AFLAC Chair in Cancer Research at the USC Norris Comprehensive Cancer Center and senior author of the study, said that the ability to differentiate between the risk for aggressive and non-aggressive forms of the disease is critical.
Refining polygenic risk scores, which assess a person's risk for a condition based on the combined influence of multiple genetic factors, using the latest findings, could help identify high-risk patients early on, added Haiman.
According to Fei Chen, Ph.D., an assistant professor of clinical population and public health sciences at the Keck School of Medicine and the study's first author, "prostate cancer survival is significantly lower among men diagnosed with aggressive disease. Our findings suggest that these polygenic risk scores could be useful for identifying men who may benefit from earlier and more frequent screenings."
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Meta-Analysis: 9 New Genetic Variants
The team conducted a meta-analysis by combining data from 10 genome-wide association studies, which provided almost all available genetic risk data for prostate cancer in men of African ancestry.
The data collected from the United States, Africa, and the Caribbean on 19,378 men with prostate cancer and 61,620 healthy controls helped identify nine previously unknown genetic variants that increased the risk of prostate cancer in men of African descent.
Seven of these variants were found mainly or exclusively in this population, highlighting the importance of including diverse populations in large-scale genetic studies.
The study revealed that one of the new variants in the 8q24 region, which has long been associated with prostate cancer risk, is only present in men of African ancestry and is influencing the risk of aggressive disease in this population.
Additionally, the researchers found that younger men have a higher genetic influence on cancer risk than older men. These new variants can be used in genetic tests to help patients determine their cancer risk and make decisions about screening frequency.
The researchers are continuing their studies of prostate cancer among African American men, including how social determinants, access to care, and other factors influence prostate cancer recurrence, progression, and survival rates.
Their long-term goal is to create a genetic screening test that is widely available to assist men of all ages in assessing their risk levels.
The findings were published in the journal European Urology.
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