CJG Blog

Center for Jewish Genetics blog

Breast Cancer Testing: Then & Now

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by Carol Guzman

In 1995, the BRCA genetic test for predisposition to breast and ovarian cancer was among the first cancer genetic test to become available for clinical use. More than 25 years after the discovery of the BRCA1 gene, research continues to identify thousands of BRCA1 and BRCA2 mutations linked to increased breast cancer risk. As more precise testing options become available, we delve into the new advances in genetic testing for breast cancer.

How has BRCA testing evolved since it was first introduced?

The demand for BRCA testing has steadily increased since researchers learned that individuals carrying pathogenic BRCA1 or BRCA2 mutations have elevated lifetime ovarian and breast cancer risk. BRCA testing conducted in 1995 was nowhere near as comprehensive as it is now. Our ability to read DNA has grown tremendously in the last few decades. In the past, BRCA tests used genotyping, a technology that examines specific locations of our DNA and compares it to reference DNA to identify differences or mutations that, at the time, were commonly known to increase an individual’s risk for cancer. Today laboratories are adopting next-generation sequencing technology, which can sequence BRCA1 and BRCA2 genes in their entirety. Think of genotyping as reading a few words on each page while sequencing allows you to read the entire chapter in a book. With next-generation sequencing, doctors will be able to analyze your genetic data as we continue to discover new BRCA mutations. 

What is the difference between BRCA testing offered by tests like 23andMe and those offered by a doctor?

Direct-to-consumer (DTC) tests, like 23andMe, are genetic tests a person can purchase over the counter or through the internet. On the other hand, a healthcare provider must order a clinical genetic test on behalf of their patient. In 2018, 23andMe received FDA approval to identify three variants in the BRCA1 and BRCA2 genes, also known as the ‘founder mutations’ because they are more commonly found among individuals with Ashkenazi Jewish ancestry. DTC tests do not take a patient’s family health history into account to determine whether more comprehensive genetic testing is necessary. There are more than 1,000 variants in the BRCA1 and BRCA2 genes known to increase cancer risk. Geneticists found that 23andMe’s genetic test could miss nearly 90 percent of participants who carried a different BRCA mutation than the three they currently offer. DTC companies also use simpler, more cost-effective technology compared to a clinic test ordered by a genetic counselor or healthcare provider. Patients who come to their doctor with DTC results must confirm their findings with a clinical test.

Beyond BRCA, are there other cancer mutations that are more common among people with Jewish ancestry? 

Yes, there are other breast cancer mutations on other genes found more commonly in individuals of Jewish ancestry though they are not as common as the founder mutations. Just last month, researchers at the Basser Center for BRCA found that a mutation on the TP53 gene was expressed most commonly in the Ashkenazi Jewish population.  Another pathogenic mutation on the CHEK2 gene was previously identified as an Ashkenazi Jewish founder mutation and increases breast cancer risk. Other genes with mutations found more commonly in people of Jewish ancestry compared to the general population include BRIP1 and PALB2. However, it’s important to note that less than 4% of Ashkenazi women who test negative for the three BRCA founder mutations still carry pathogenic mutations on other genes

As scientific technologies develop more comprehensive genetic testing, talk to your healthcare provider to see whether new genetic tests can provide a deeper insight into your genetic health. The Norton & Elaine Sarnoff Center for Jewish Genetics offers a wealth of resources for persons who want to learn more about their risk and options for testing, prevention, and early detection. These resources include information on our website, JewishGenetics.org, and community access to a genetic counselor who is available to provide education, answer questions, and direct individuals to appropriate clinical resources.

Making Science More Accessible through Dance

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By Masha Bandouil

I am a senior Dance and Biology double major at Loyola University of Chicago, currently researching how dance can make science more accessible to the general public. Over the last year, I produced three dance films that translate educational text from the Sarnoff Center website into the language of movement. The films illustrate and explain the principles of genetics, as well as genetic diseases and hereditary cancers that disproportionately affect the Jewish community. While there is a voice-over for the films, I am interested in my choreography as the principle form of communication.

Rooted in human instinct, the body houses knowledge that is just as important to access as the knowledge associated with the mind. Ranging from gestures to dance steps, I believe movement can provide a universal language through which scientists can share their findings with non-scientific audiences despite barriers of language, learning style, education level, or access to specialized knowledge.

The first film is an overview of the basics of genetics and can be found in the Genetics 101 tab.

The second film explains genetic diseases and can be found in the Jewish Genetic Disorders tab.

The third film explains hereditary cancers and can be found in the Hereditary Cancer Overview tab.

Check out the films and see if the dance imagery helps you better visualize and understand the scientific concepts! Fill out the survey that accompanies the films and let me know your thoughts - I would love to hear what you think!

What Makes a Jewish Genetic Disorder 'Jewish?'

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WorldEuropePinsBy Haley Fuoco

      As my internship at the Sarnoff Center wraps up, I wanted to share an overview of my research this summer on how to define a Jewish genetic disorder and to understand the commonalities between seemingly different Jewish genetic disorders. 

      Jewish genetic disorders vary in their severity, age of onset, carrier frequencies, and treatment options. Despite these differences, they have at least one commonality: their link to the founder effect. The founder effect theorizes that most Ashkenazi Jews alive today descended from a group of only a few thousand individuals, or “founders,” who lived in Eastern Europe 500 years ago. Thus, even if just a few of these individuals or founders had a mutation, those mutations would increase in frequency over time. There is no set carrier frequency used to define Jewish genetic disorders, although they all have high carrier frequencies among individuals of Ashkenazi Jewish descent because of the founder effect.

      Various organizations have different definitions as to which genetic disorders fall under the umbrella term “Jewish genetic disorders.” Some genetic testing companies recognize 18 to 19 genetic disorders as Jewish genetic disorders. However, there is a growing recommendation that individuals with Jewish ancestry receive expanded carrier screening over targeted Jewish ancestry panels to increase carrier detection effectiveness. Expanded carrier screening is more effective than targeted Jewish ancestry panels because many individuals come from mixed ancestry or might not know their ancestry. One study concluded that the research on Jewish genetic disorders still has a long way to go but community-based testing organizations, like the Sarnoff Center, are ahead of the current research by offering larger expanded carrier screening panels. 

      As the size of carrier screening panels increases, there might be an increase in the number of genetic disorders that have high carrier frequencies in individuals with Jewish ancestry. Therefore, Jewish genetics continues to evolve. The Sarnoff Center continues to adapt to the increase of information on Jewish genetics to ensure the community is well informed and has access to a subsidized carrier screening for more than 200 genetic disorders. To learn more about the Sarnoff Center’s affordable, accessible carrier screening program or to speak with a genetic counselor visit jewishgenetics.org/get-screened or contact us at GeneticScreening@juf.org.



Affordable, Accessible Genetic Screening in Illinois



Do You Know What's In Your Genes?

