The genetic threat rating can be utilized to find out the chance of creating prostate most cancers
Some racial and ethnic groups suffer from general ailments relatively more frequently and far worse than others. Prostate cancer is a disease that has such health disparities: the risk for the disease is about 75 percent higher, and prostate cancer is more than twice as fatal in blacks than whites.
However, whites are often over-represented as research participants, making these differences difficult to understand and ultimately address.
With this in mind, scientists from the USC Center for Genetic Epidemiology and the Institute for Cancer Research in London conducted a study that summarized data from most studies on genomic prostate cancer worldwide.
With more than 200,000 men of European, African, Asian, and Hispanic ancestry from around the world, the study is the largest and most diverse genetic analysis ever done for prostate cancer – and possibly any other cancer.
The paper appears today in Nature Genetics.
The study's authors identified 86 new genetic variations that increase the previously undiscovered risk of prostate cancer and bring the total number of prostate cancer risk locations to 269.
Using a model to assess prostate cancer risk based on the interplay of these genetic factors, the researchers showed that, on average, African men inherited about twice as much prostate cancer risk as European men, while Asian men inherited about three people. Quarter of the risk of their white counterparts – evidence that genetics plays a role in differences in how often cancer occurs among racial groups.
This research is also a step towards the application of precision medicine for early diagnosis.
Our long-term goal is to develop a genetic risk score that can be used to determine a man's risk of developing prostate cancer. Men at higher risk may benefit from earlier and more frequent screening so that the disease can be identified when it is more treatable. "
Christopher Haiman, ScD, Corresponding Study Author, Professor of Preventive Medicine, USC's Keck School of Medicine, and Director of the USC's Center for Genetic Epidemiology, USC's Keck School of Medicine
Study looks at health inequalities
Jonathan W. Simons, MD, President and Chief Executive Officer of the Prostate Cancer Foundation, praised the study's potential for increasing health equity. The foundation funds Haiman's other work leading the RESPOND initiative to study the disease in African American men.
"PCF believes that Dr. Haiman's research will lead to more effective precision screening strategies for prostate cancer in men of West African descent," said Simons. "PCF is certain that identifying these very high risk individuals will have a positive impact on this significant health inequality."
Haiman and his colleagues used genomic datasets from countries such as the US, UK, Sweden, Japan, and Ghana to compare 107,247 men with prostate cancer with a control group of 127,006 men. By examining a spectrum of races and ethnicities, the study's authors aim to make the genetic risk score more useful to more people.
"Not only did we find new risk markers, but we also showed that by combining genetic information across populations, we were able to identify a risk profile that can be applied across populations," said Haiman. "This underscores the value of including multiple racial and ethnic populations in genetic studies."
Risk assessment could help improve screening
Today's screening guidelines for prostate cancer suggest that those 55 years of age and older who are at moderate risk can perform the prostate specific antigen test (PSA) in consultation with their doctors. High levels of PSA are linked to prostate cancer, but the PSA test tends to detect slow-growing tumors. When used widely, this too often leads to unnecessary treatment.
The value of the PSA test as a screening tool would increase if it were used selectively to monitor people who are at high risk of prostate cancer. This is where the genetic risk score could come into play. People at particularly high risk can start screening even before the age of 55.
A large-scale clinical study would be required to translate the current research results into better early detection.
"In contrast to previous screening studies, this one would have to be more representative of the diversity we see in the world," said Haiman. "No population should be left behind."
USC's Keck School of Medicine
Conti, D.V. et al. (2021) The genome-wide association meta-analysis of prostate cancer between ancestors identifies new susceptibility sites and provides information on the prediction of genetic risk. Natural genetics. doi.org/10.1038/s41588-020-00748-0.