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Does expanded genetic testing benefit Jewish women diagnosed with breast cancer?


This research is relevant for:

Checked Breast cancer survivors

Checked Women under 45

Checked Women over 45

Unhecked Men with breast cancer

Unhecked Metastatic breast cancer

Unhecked Triple negative breast cancer

Checked Previvors

Unhecked BRCA mutation carriers

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Unhecked Her2+ breast cancer

Checked Special populations: Jewish women diagnosed with breast cancer

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Carrying a BRCA gene mutation increases the risk of cancer in both women and men. Such information is valuable for people diagnosed with cancer and can affect medical decisions for both the patient and his or her family members. Approximately 2% of people of Ashkenazi Jewish (Eastern European) descent carry one of three common BRCA gene mutations. For Ashkenazi Jewish women diagnosed with breast cancer who do not carry one of the three common BRCA mutations, little is known about their chance of carrying another hereditary mutation that may increase risk. This study looked at how often Ashkenazi Jewish women diagnosed with breast cancer were found to carry mutations other than the three common BRCA gene mutations found among individuals of Ashkenazi Jewish descent. (09/13/17)


STUDY AT A GLANCE

This study is about:

The benefit of doing additional genetic testing for Jewish breast cancer survivors who tested negative for the three common Jewish BRCA mutations. Researchers wanted to examine if additional genetic testing would find other inherited mutations within BRCA1, BRCA2, or in other genes that also increase risk of breast cancer. 

Why is this study important?

A founder mutation are a mutation that is common in people of a distinct population. In the Ashkenazi Jewish population, three founder mutations, two in BRCA1 and one in BRCA2 have been identified. Ashkenazi Jewish women who carry one of these mutations are at much greater risk of being diagnosed with breast and/or ovarian cancer than Ashkenazi women who do not carry a founder mutation. Having this information can help guide women in their breast cancer treatment choices. But what about Ashkenazi Jewish women diagnosed with breast cancer who test negative for the BRCA founder mutations?  What is the chance they may have inherited a unique BRCA mutation or a mutation in another breast cancer gene? How does knowing this additional genetic information affect their medical decisions and health outcomes? 

Study findings: 

  • This study tested 1,007 Ashkenazi Jewish women with breast cancer for mutations in 23 different breast cancer genes.
    • 903 of these women did not carry any of the three BRCA founder mutations. 
      • 7 women (0.8%) carried a unique mutation in BRCA1 or BRCA2.
      • 31 women (3.4%) carried a harmful mutation in another breast cancer gene.

What does this mean for me?

  • If you are an Ashkenazi Jewish women diagnosed with breast cancer:
    • If you have never had genetic testing, speak with your health care provider about genetic counseling and testing for a BRCA or other inherited mutation which can cause breast cancer.
    • If you had genetic testing only for the three founder BRCA mutations commonly found in Jewish people and you tested negative, you may consider talking to your health care provider about expanded genetic testing for other mutations within BRCA1, BRCA2, as well as in other breast cancer genes. 
    • Expanded genetic testing is considerably less expensive than it was even four years ago, and is often covered by insurance. Knowing the results can help patients make risk reduction and treatment choices, as well as help guide screening decisions for family members.
    • Family history should not be used as the only measure when considering genetic testing.
      • Among all Ashkenazi Jewish women in this study who tested positive for a mutation, approximately half did not have a family history of cancer.
  • If you have been diagnosed with breast cancer and you are not of Ashkenazi Jewish descent, talk to your health care provider about whether you meet the national guidelines for genetic counseling and testing. 

Questions to ask your health care provider:

  • I previously tested negative for the BRCA founder mutations. Should I be tested for other BRCA mutations?
  • Should I be tested for mutations in other, non-BRCA breast cancer genes?
  • If I test positive for a mutation in other breast cancer genes, what does that mean for me and my family as far as screening, cancer prevention, and treatment choices?

IN-DEPTH REVIEW OF RESEARCH

Study background:

Both men and women who carry a BRCA mutation have a significantly increased lifetime risk of several types of cancer. People of any race or ethnicity can test positive for a BRCA1 or BRCA2 mutation.  Between 1 in 400 and 1 in 800 people in the general U.S. population has an inherited BRCA mutation. That number increases to about 1 in 40 among people of Eastern European Jewish descent. However, many Ashkenazi Jewish women who have been diagnosed with breast cancer test negative for the three founder mutations. In the past, when the cost of genetic testing was much higher, Jewish people with breast cancer sometimes might only undergo limited genetic testing looking only for the three most common founder mutations. Drs. Tom Walsh, Mary-Claire King, and colleagues published a retrospective study in JAMA-Oncology looking at mutations in known and suspected breast cancer genes among the New York Breast Cancer Study Participants. They wanted to know if these women would benefit from genetic sequencing of all breast cancer genes, including BRCA1 and BRCA2, in addition to targeted testing for the Jewish BRCA founder mutations.

Researchers of this study wanted to know:

How common are unique mutations in BRCA1 and BRCA2 and how common are mutations in other breast cancer genes in Ashkenazi Jewish women diagnosed with breast cancer?

Population(s) looked at in the study:

Researchers looked at DNA and data collected from 1996-2000 from 1,007 participants in the New York Breast Cancer Study (NYBCS). All participants were Ashkenazi Jewish women diagnosed with invasive breast cancer, and were not selected based on family history or age at diagnosis. Their DNA had previously been studied for the three common Jewish BRCA mutations. In this new study, researchers used a panel test to identify unique mutations in BRCA1, BRCA2, and other genes known to increase breast cancer risk. They looked at results based on BRCA status, family history, and age at diagnosis.

Study findings:

Of the 1,007 patients in the study:

  • 104 women (10.3%) had a BRCA1 or BRCA2 founder mutation.
    • These women were more likely to be younger at age of diagnosis and more likely to have a family history of breast or ovarian cancer than were patients with no founder mutation.
  • 903 (90%) had none of the three Jewish founder mutations in BRCA1 or BRCA2.
    • Of these 903 women, 865 women tested negative for any known mutation associated with breast cancer
  • A total of 142 women in the NYBCS tested positive for any mutation. Of these women:
    • 104 (74%) had a BRCA founder mutation
    • 7 (5%) had a non-founder BRCA mutation
    • 31 (22%) had a mutation in another gene
      • 29 of these mutations were in the CHEK2 gene
        • Of the 29 CHEK2 mutations, 24 were a known Ashkenazi Jewish founder CHEK2 mutation, c.1283C>T. The other five CHEK2 mutations are common in people of European descent.
      • 1 mutation each was found in BRIP1 and NBN
    • Approximately half of women with an inherited mutation in a breast cancer gene had no family history of breast or ovarian cancer.

Limitations: 

  • This study looked only at Ashkenazi Jewish women with invasive breast cancer. Women who were not Ashkenazi Jewish, had non-invasive breast cancer or ovarian cancer, or were cancer-free were not studied.
  • Researchers tested only some known breast cancer genes for mutations. Mutations in other cancer genes, such as genes for Lynch syndrome, were not examined.
  • The panel test used in this study examined 23 different genes. Although scientists know a lot about many of them, they are still studying these and other genes, meaning cancer risk information is limited and expected to change with further research.
  • There are likely mutations that increase risk of breast cancer in other, unknown genes

Conclusions:

The results of this study suggest that Ashkenazi Jewish women who have been diagnosed with breast cancer and have tested negative for the three BRCA founder mutations should talk to their health care provider to see if they should consider genetic testing for other mutations in BRCA1, BRCA2 as well as other breast cancer genes.  Share this study with your health care provider to see if additional genetic testing makes sense for you.

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Posted 9/13/17

Reference

Walsh T, Mandell JB, Norquist BM, Casadei S, Gulsuner S, Lee MK, King MC. Genetic Predisposition to Breast Cancer Due to Mutations Other Than BRCA1 and BRCA2 Founder Alleles Among Ashkenazi Jewish Women. JAMA Oncol. 2017. Jul 20. doi: 10.1001/jamaoncol.2017.1996. [Epub ahead of print]

Related Information and Resources

Cancer Risk: Breast Cancer

Hereditary Cancer: Hereditary Cancer & Genetics

Hereditary Cancer: Genetic Testing for Hereditary Cancer

Hereditary Cancer: Genes Associated with Hereditary Cancer

Who Should Consider Genetic Testing? Genetic testing for people who are Jewish or have Jewish ancestry

Who Should Consider Genetic Testing? Genetic testing for women with breast cancer

Special Populations: Jewish People

Publication: What Every Jewish Family Should Know about Breast and Ovarian Cancer 

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