New research was published in JAMA Oncology last week finding that Ashkenazi Jewish women with breast cancer may carry a different mutation in the BRCA1 or BRCA2 genes than commonly shown to cause the disease. Another percentage of Ashkenazi Jewish patients also hold a mutation in another gene that predisposes them to breast cancer.
Researchers from the University of Washington performed multiplex genomic testing among 1007 breast cancer patients with Ashkenazi Jewish ancestry. The researchers looked at all known breast cancer genes.
Out of those patients with a BRCA1 or BRCA2 gene mutation, 0.8 percent carried a separate mutation from the one that typically causes breast cancer. Additionally, 3.4 percent of patients with Ashkenazi Jewish ancestry had a mutation in another gene that predisposed them to breast cancer.
These researchers advise breast cancer patients with Ashkenazi Jewish ancestry to undergo genetic testing so that their family members and offspring can have a better idea of their breast cancer risk.
The study states that three different mutations in BRCA1 and BRCA2 genes among Ashkenazi Jewish women significantly increase their risk of both breast and ovarian cancer.
Learning about other types of genetic mutations that increase breast or ovarian cancer risk can help women better understand ways to prevent the disease as well as get diagnosed early and save their own life. Women from 12 different cancer centers were followed and the parameters required patients with all four grandparents of Ashkenazi Jewish ancestry.
The genomic DNA was first analyzed between 1996 to 2000. The study design and data analysis took place between 2014 to 2017. As many as 23 known and candidate breast cancer genes were analyzed.
Some of the other genes in Ashkenazi Jewish patients tied to breast cancer risk include CHEK2, BRIP1 and NBN. The results show that 14.1 percent of all Ashkenazi Jewish patients in the study carried a mutation responsible for their breast cancer. As many as 11 percent of the subjects had a BRCA1 or BRCA2 genetic mutation and 3.1 percent had a CHEK2 or other breast cancer gene mutation.
Out of the 111 patients with BRCA1 or 2 gene mutations, slightly more than half had a mother or sister with ovarian or breast cancer. It is also important to note that about half of all patients in the study with a genetic mutation in a breast cancer gene did not have any family history of the disease.
This shows that women should be aware they may be at higher risk of the disease even if no close family members were diagnosed with breast cancer. Some of the genetic predisposition for the disease among these women may have been inherited from their father’s side.
Limiting genetic testing to women with only a family history of the disease may miss about half of all Ashkenazi Jewish women at genetic risk of breast cancer. Right now, there is a general recommendation for all breast cancer patients with Ashkenazi Jewish ancestry.
However, this recommendation of testing women after they are diagnosed with cancer may limit the use of precision medicine. It is possible that finding genetic mutations before a woman is diagnosed with cancer may play a role in preventing the disease from developing.
The researchers suggest providing genetic testing as part of routine medical care to all women before they end up diagnosed with breast cancer.