ASCO 2021: Clinical Validation of Breast Cancer Risk Testing for People of All Ancestries

The Myriad Genetics team, together with leading healthcare collaborators, has been hard at work to expand access to reliable genetic testing results. The result is a new approach for measuring the risk of developing breast cancer in women of all ancestries.

At the recent annual meeting of the American Society of Clinical Oncology (ASCO), an important clinical validation study of this approach was presented by Dr. Holly Pederson, Director of Medical Breast Services at Cleveland Clinic and one of the researchers involved in the study.

Her insightful presentation is available to watch on-demand, but if you don’t have time, here are some of the highlights.

The challenge, Dr. Pederson reported, is that genetic markers used to calculate the risk of developing breast cancer are not distributed evenly across all populations. When risk testing is based on genetic markers found in people of a certain ancestry, the results may be less accurate for people of different ancestries. Because so many of the early genetic studies were performed in European populations, many current genetic tests provide less reliable results for patients who are of non-European ancestry. For example, Dr. Pederson noted that breast cancer risk scores tend to be artificially high among non-Europeans.

To get more accurate results for people of any ancestry, risk scoring has to be re-engineered to account for the frequency of different genetic markers in various populations. The Myriad Genetics approach to this involves assessing each person’s ancestry based on genetic data as part of the risk analysis, and then using that information to weight the breast cancer markers accordingly. Myriad uses more than 50 data points to determine ancestry, and more than 90 markers associated with the risk of developing breast cancer.

This approach was developed based on a study of nearly 190,000 women and validated — with the help of Dr. Pederson and other clinical researchers — in a separate study of more than 89,000 women. Results showed that the new method of risk scoring was more accurate for people of all ancestries, indicating that weighting risk based on ancestry will make it possible to deliver more reliable results to everyone.

“We developed a framework for a [risk scoring approach] that is accurate for women of all ancestries and can be adapted as additional data becomes available,” Dr. Pederson said.

“Thanks to this clinical validation, Myriad Genetics is now the only company to provide accurate breast cancer risk assessment for women of non-European ancestry, which could help increase access and reduce disparities for those at risk of breast cancer,” said Jerry Lanchbury, Ph.D., chief scientific officer of Myriad Genetics. “Development of the planned commercial model that incorporates clinical and family history factors in addition to the genetic component has been submitted to the 2021 San Antonio Breast Cancer Symposium. We aim to get this crucial test to all women through the riskScore^® breast cancer risk assessment tool soon, which is part of the Myriad MyRisk^® Hereditary Cancer test.”