Changes to genetic tests can improve the accuracy with which they assess breast cancer risk for women from Ashkenazi Jewish backgrounds, British researchers reported last night.
While some genetic tests can tell women their personal risk of developing breast cancer, they have been found to be inaccurate for many Black, Asian or Ashkenazi Jewish women, or women with a mixed ethnic background.
A new study by researchers at Manchester University NHS Foundation Trust (MFT) and The University of Manchester, supported by the National Institute for Health and Care Research (NIHR) Manchester Biomedical Research Centre (BRC), and a team in Israel, investigated how to improve breast cancer genetic tests for Ashkenazi Jewish women.
The tests look for Single Nucleotide Polymorphisms (SNPs), which, depending on the unique combination of them, can increase or decrease the risk of breast cancer.
This information is used to produce a Polygenic Risk Score (PRS), which can inform women whether they are at low, average, or high risk of developing breast cancer in the next 10 years.
In this new study, researchers used genetic information from Ashkenazi Jewish women in both Manchester and Israel, with data from the Predicting the Risk of Cancer at Screening (PROCAS) study conducted in Greater Manchester, and the Breast Cancer in Northern Israel (BCINIS) study.
They compared two available PRS based on two SNPs – SNP142 and SNP78 – and analysed their accuracy for women of Ashkenazi Jewish ancestry.
The findings, published in Genetics in Medicine, showed that these PRS tests inaccurately predicted Ashkenazi Jewish women to be at higher risk of developing breast cancer, but after adjusting the test, they generated a more accurate prediction of breast cancer risk for them.
Study leader Professor Gareth Evans said: “Polygenic Risk Scores (PRS) are a major component of accurate breast cancer risk prediction and have great potential to improve personalised screening methods. However, it is clear from our findings that you cannot simply apply current PRS developed using genetic data from individuals of white European ancestry to those from Ashkenazi Jewish backgrounds.
“A test result which exaggerates a woman’s risk of the disease could lead to undue stress or concern and unnecessary screening and preventative measures that they don’t need. Future PRS for Ashkenazi Jewish women should be based on their genetic data to provide a more accurate risk prediction.
“This study is an important step forward in our continued research into breast cancer genetic testing for people of different ethnic backgrounds to improve equity. More accurate and personalised PRS are required to avoid further increasing health inequalities and so patients can receive high-quality screening, care, and treatments.”
Roberts E, van Veen EM, Byers H et al. Breast cancer polygenic risk scores derived in White European populations are not calibrated for women of Ashkenazi Jewish descent. Genetics in Medicine 3 July 2023
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