Breast Cancer Genetic Testing

Jill E. Stopfer
Last Modified: November 1, 2001

Dear OncoLink "Ask the Experts,"

I had genetic testing performed and they found a change called N6OS in BRCA2.

This was the first time this change had been detected. Although they said it occurred in the area of the gene thought to be functionally significant, since it was a substitution rather than a truncation, it was uncertain whether or not it was associated with an increased risk of breast or ovarian cancer. I was wondering if anyone involved in research might be able to shed any light on the nature of this change for me? I have had genetic counseling and am doing excellent cancer-wise. I come from a "research" family and am just trying to seek out any emerging information regarding breast cancer genetics.
Thanks so much for any help you can give me or any other resource you can refer me to!
PL

Jill E. Stopfer, MS Certified Genetic Counselor for the University of Pennsylvania Cancer Risk Evaluation Programs, responds:

It appears as though you may have a variant of uncertain significance in your BRCA2 gene. You can think of it as an alternative spelling of a gene that may or may not be a problem. There are quite a few families with this finding, since the BRCA2 gene is so large, and sequencing of many families has only started fairly recently. If you were tested through a research group, they might offer to test other family members to see if the variant tracks with cancer risk. That is, do all the people with cancer in the family have the variant, while the people without cancer do not have the variant. When this is the case, it is more evidence supporting the variant being harmful. When the variant doesn't track with cancer risk, it's more evidence that it is not the source of cancer risk in the family.

You can ask the genetic counseling group you are working with if they have looked recently in the BIC database for this specific variant. They probably have, and that's why they told you it hasn't been reported before. It's just one more thing to ask about, and then check in periodically (6 month intervals) with the research group you to see if anything more has been reported about your BRCA2 variant.