% risk for daughters of moms with bc?

The risk is 50/50..my oldest daughter was recently tested (positive)and we are

awaiting results for my youngest daughter. That is what they were told..

I had  bc stage 0 -15 years ago at age 37  and now stage 4 , my mom had it, her mom and my aunt. My sister tested

negative. So her daughters (my neices) will not have the gene.

Only a small number of women who seek genetic testing will get a test result that says they have a breast cancer gene abnormality. About 2% of women with no significant family history of breast cancer, and less than 20% of women with a significant family history, will have positive test results. And only some of the women who find out they have a breast cancer gene abnormality decide to take some action to reduce their risk (for example, having risk-reducing surgery, which removes the breasts, ovaries, or both, or taking anti-estrogen drugs).

The task force also found that the results of genetic testing can be confusing and even misleading. For example, a woman with a strong family history of breast and ovarian cancer may get a test result that says, "no abnormality of BRCA 1 or BRCA 2 is present" (this is a "negative" test result). But this test result may be falsely reassuring. There may be another gene abnormality in her family that just hasn't been discovered yet. So a woman in this situation may still be at high risk for breast cancer (and ovarian cancer). She will still need to consider taking steps to reduce her risk, and she'll still need to be carefully monitored by her doctors.http://www.breastcancer.org/risk/genetic/new_research/20051003.jsp





Since about 70% of women who get breast cancer have NO obvious risk factors (besides being a woman) its really hard to predict who will get bc and who won't.

I was considering the genetic testing when I was first diagnosed.  I am 47 and there is no history of bc on my mom's side of the family but my dad's side is unknown.  I was adopted by my father at age 4 and  have never met or cared to meet my biological father.  I have a friend who works at a cancer center in northern Ontario and she spoke to her genetic counselor there.  She told me basically the same things that are posted here in this thread.  I decided like Pam not to be tested and just get my daughter to be more vigilant when it comes time, she is 13 years old.  I also told my sisters they need to be really vigilant now as well ( one is 41 the other 37), on my dad's side ( adopted father which is there bio dad) there is history of bc.  My aunt, and multiple great aunt's. 

The breast cancer risk for a daughter of a BC mother is not 50/50.  That would be the risk that a daughter might be carrying the BRCA genetic mutation if her mother carries it.  But that's not the same as the risk of getting BC, even for someone who carries the gene.  And to leaf's point, it's very important in this discussion that we separate out those who carry the BRCA genetic mutation from those who don't.

If a mother carries the BRCA genetic mutation, then there is a 50/50 chance that her daughter will inherit the BRCA gene.  With the gene, depending on whether it's BRCA1 or BCRA2, and depending on the specific variant, the risk of breast cancer ranges from about 25% to about 60% (or possibly higher).  If a mother carries the BRCA genetic mutation, then there is a 50% chance that her siblings - brothers and sisters -  do too.  But there is no way to know if they carry the gene unless they are tested.  If a sibling is also found to carry the BRCA gene, then his/her children have that same 50/50 chance of inheriting it.  If on the other hand a sibling does not carry the gene, then his/her children have no chance of carrying it (unless they happened to inherit it from their other parent).  So doing the math, that means that a niece of someone who carries the BRCA genetic mutation has a 25% chance that she too may carry it. 

Then there are mothers who have BC who don't carry the BRCA genetic mutation.  This situation isn't as clear (as if the other situation is clear!).  If there is a strong family history of BC, there could be another genetic link that simply hasn't been discovered yet.  That would increase the risk to the daughter, but by an unknown amount (since the cause is genetic, but unknown).  In most cases, however, there is no genetic cause for breast cancer.  Approx. 85% of breast cancers are not genetic.  In these situations, there may be no increased risk to the daughter but this isn't 100% certain either.  That's why most risk models include immediate family w/ breast cancer as an increased risk factor.  It could be that family members were exposed to the same external/environmental risks.  Or it could be that there is an inherited link separate from the genetic mutation.  For example, it's been shown that those who have dense breast tissue are at greater risk of BC.  If a mother has dense breast tissue and her daughter has inherited that trait, the daughter might have an increased risk of breast cancer.  

It's certainly not a simple topic or a very clear one.  But in the end, as leaf said, most women who are diagnosed with BC don't have any glaring risk factors.  Approx. 1 in every 8 women in North America will be diagnosed with breast cancer; most of these women do not have a family history.

Caya, you sound just like me...

I was dx 1 month before my 50th b-day.

No cancer in my family that I am aware of of any kind.  Dad was  Ashkenazi Jewish so I was tested.

No BRCA1/2 ...mom still alive at 84 this year and still no BC.  Twin sister, no BC (knock on wood).

Hi all,

My background includes a Ashkenazi great-grandfather, and I have a rare subgroup of BC usually associated with BRCA mutation. Yet I tested negative. Whew! However, my daughters and granddaughters will be extra careful.

Love to all,

Annie