What Do We Know About Hereditary Breast Cancer in Ashkenazi Jews?
In 1995 and 1996, studies of DNA samples revealed that Ashkenazi (Eastern European) Jews are 10 times more likely to have mutations in BRCA1 and BRCA2 genes than the general population. Approximately 2.65 percent of the Ashkenazi Jewish population has a mutation in these genes, while only 0.2 percent of the general population carries these mutations.
Further research showed that three specific mutations in these genes accounted for 90 percent of the BRCA1 and BRCA2 variants within this ethnic group.
This contrasts with hundreds of unique mutations of these two genes within the general population. However, despite the relatively high prevalence of these genetic mutations in Ashkenazi Jews, only seven percent of breast cancers in Ashkenazi women are caused by alterations in BRCA1 and BRCA2.
What Other Genes May Cause Hereditary Breast Cancer?
Not all hereditary breast cancers are caused by BRCA1 and BRCA2. In fact, researchers now believe that at least half of hereditary breast cancers are not linked to these genes.
Scientists also now think that these remaining cases of hereditary breast cancer are not caused by another single, unidentified gene but rather by many genes, each accounting for a small fraction of breast cancers.
Is There a Test for Hereditary Breast Cancer?
Hereditary breast cancer is suspected when there is a strong family history of breast cancer: occurrences of the disease in at least three first or second-degree relatives (sisters, mothers, aunts). Currently, the only tests available are DNA tests to determine whether an individual in such a high-risk family has a genetic mutation in the BRCA1 or BRCA2 genes.
When someone with a family history of breast cancer has been tested and found to have an altered BRCA1 or BRCA2 gene, the family is said to have a “known mutation.”
Positive test results only provide information about the risk of developing breast cancer. The test cannot tell a person whether or when cancer might develop.
Many, but not all, women and some men who inherit an altered gene will develop breast cancer. Both men and women who inherit an altered gene, whether or not they develop cancer themselves, can pass the alteration to their sons and daughters.
But even if the test is negative, the individual may still have a predisposition to hereditary breast cancer. Currently, available techniques can’t identify all cancer-predisposing mutations in the BRCA1 and BRCA2 genes. An individual may also have inherited a mutation caused by other genes.
Because most breast cancer cases are not hereditary, individuals may develop breast cancer whether or not a genetic mutation is present.
How Do I Decide Whether to Be Tested?
Genetic counselors can help individuals and families make decisions regarding testing.
For those who do test positive for the BRCA1 or BRCA2 gene, surveillance (mammography and clinical breast exams) can help detect the disease early.
A woman who tests positive can also consider taking the drug tamoxifen, which has been found to reduce the risk of developing breast cancer by almost 50 percent in women at high risk.
Clinical trials are now underway to determine whether another drug, raloxifene, effectively helps prevent breast cancer.
Interested in Learning More?
If you’d like to schedule your consultation with Dr. Sadeghi, click here or call (504) 322-7435. You can discuss your family history of breast cancer and determine if you should be tested for the BRCA gene mutation.
While the exact cost may vary on several factors, the average cost of the BRCA gene mutation test is $250. You will be provided with more information when you contact Sadeghi Plastic Surgery.