Genetic Testing and the Jewish Community

Most of you are well aware of the growing number of mutations that increase a person's risk of cancer. The best known are the BRCA1 and BRCA2 genes that have been linked to hereditary breast and ovarian cancers. Mary-Claire King PhD, a University of Washington professor of genome sciences and medicine discovered the "breast cancer gene", BRCA1 on chromosome 17, which is responsible for a number of different inherited breast and ovarian cancers. This led to the later discovery of BRCA2. 

The NCI gives this summary: 

Breast cancer: About 12% of women in the general population will develop breast cancer sometime during their lives (1). By contrast, a recent large study estimated that about 72% of women who inherit a harmful BRCA1 mutation and about 69% of women who inherit a harmful BRCA2 mutation will develop breast cancer by the age of 80 (2).

Like women from the general population, those with harmful BRCA1 or BRCA2 mutations also have a high risk of developing a new primary cancer in the opposite (contralateral) breast in the years following a breast cancer diagnosis. It has been estimated that, by 20 years after a first breast cancer diagnosis, about 40% of women who inherit a harmful BRCA1 mutation and about 26% of women who inherit a harmful BRCA2mutation will develop cancer in their other breast (2).

Ovarian cancer: About 1.3% of women in the general population will develop ovarian cancer sometime during their lives (1). By contrast, it is estimated that about 44% of women who inherit a harmful BRCA1mutation and about 17% of women who inherit a harmful BRCA2 mutation will develop ovarian cancer by the age of 80 (2).

https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet#q2

I am thinking about this today because of a recent evening event about the Jewish Connection to Breast Cancer. The basic statistic in the US is that women have a 1-in-8  (or 12%) lifetime risk of developing breast cancer. Women with an Ashkenazi Jewish heritage can have up to an 80% risk. This is obviously a huge difference and very scary for women in this group. There is a new push by One in Forty (http://oneinforty.org) and other groups to get the word out to younger Jewish women who may not be aware of this risk. 

Over the years, I have worked with a number of young women who have tested positive for the gene mutation, and the choices are wrenching. Should I have bilateral mastectomies? If so, when? Before or after having and perhaps nursing my children? What about having my ovaries removed? Although that surgery is less obvious, it makes an enormous physiological difference and often an equally large psychological one to a young woman.

There was a recent event in Boston about this issue, and I am grateful to Ginny, who attended, for this summary:

• 90% of the Jews in the US are of Ashkenazi heritage
• People of Ashkenazi heritage are 10 times more likely than others to have BRCA-1 or BRCA-2 gene mutations that lead to breast (male & female), ovarian, AND pancreatic cancers.
• Children with 1 parent (mother or father) who is BRCA-1 or BRCA-2 positive are 50% likely to be BRCA-1 or BRCA-2 positive
• Men and women who had BRCA testing years ago may want to update their family tree, have genetic counseling and THEN updated “panels” (more testing beyond BRCA and including the newer BRCA testing)
• Those of us who have had BC diagnoses know about genetic testing; the rest of the American population does not have a clue.  We need to learn more and become the evangelists for genetic testing.  To save lives, we need to talk to everyone we know (especially Jewish friends) about genetic testing and WHO needs it.
• The “crime” is that healthy, young Jewish women (under age 30) do not know about 
• The newest BAD RESULT is that new cancer diagnoses at young ages that could be prevented by genetic testing -- especially among young Jewish women.

Learn more about genetic risk for cancer

• Cancer Genetics and Prevention Program