Genetic question..

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Papillon1
Papillon1 Member Posts: 308
edited June 2014 in High Risk for Breast Cancer

so I have been told I have a 1 in 4 chance of getting breast cancer. Probably not BRCA so they aren't testing. So I have a familial risk. Moderate risk.

My question is about the genetics of breast cancer. If my mum has HER2+ , ER+ breast cancer (as she does) and her mum had a different type of breast cancer would that influence the genetic risk I am given? In actual fact I don't know what type my grandmother had, but I am curious..the 1 in 4 chance I was given didnt take types of breast cancer into account..it was never discussed in my genetic consultations. But it has since been brought up by my mothers oncologist.  Does the type of cancer affect the genetic predisposition to breast cancer an individual may have?

Or does the familial risk I have perhaps mean we have a tendancy towards contracting breast cancers of any type...or would that not work, would it usually be the same type? Confused..

I had been discussing double mastectomy with a surgeon. I was comfortable and happy I have the option to take action now. But then my mums oncologist randomly said that the fact her and her mum both had breast cancer was just coincidence. I wonder if he knows about the type of breast cancer my grandmother has ....my genetic counsellors are in a different country to my mums doc, and getting doctors to discuss details  and get the right answers across borders is a nightmare....

Confused.com.

Am just hoping there is a genetic expert out there who can shed some light...thanks xxx

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  • BayouBabe
    BayouBabe Member Posts: 2,221
    edited April 2014

    I am confused.  How can they say "probably not BRCA" without testing???  I have no family history of breast cancer, but am BRCA +.  A "guess" about familial genetics doesn't sound right to me.  

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  • DiveCat
    DiveCat Member Posts: 968
    edited April 2014

    Bayou,

    In some cases they will not test without at least 10% chance of a positive test. This calculation is based on number and types of cancer  (i.e. TN) in family, ages at onset, ancestry, if there is male breast cancer, whether there has been any positive testing or negative testing in family, etc. 

    As the OP has no personal hx of cancer, the hurdle can be a bit higher.

    The majority of hereditary breast cancers are NOT BRCA-related.

    Papiilon,

    It is hard to say. ER+ and HER+ are both LESS common in BRCA1+ for example, but ER+ is more common in BRCA2+, but this does not mean the reverse is impossible. Some cancers, like triple negative, are more of a red flag for possible genetic risks. But different hormone receptors through the family does not necessarily indicate it is not genetic either.  There is still a lot "unknown" about the intricacies of breast cancer. Even in BRCA1+ families, sometimes there are ER+ cancers though the majority are triple negative.

    Of course, they also used to not test/be able to test hormone receptors either so sometimes there is no way to trace a pattern.

    At what ages were your mother & grandmother dx'd? That is usually more indicative of hereditary risk. 2 relatives under 50, for example, is usually a flag. 2 at a much older age of onset may be more a matter of sporadic cancer (though not always). Sometimes entirely sporadic cancers happen even in closely related relatives.

    My genetic counselors, breast specialists, medical oncologists never cared much about the particulars of the hormone status of my family cancers (and I only know my mothers....they did not test when my grandmother/great grandmothers were diagnosed/alive). They just looked more at the number of affected, their age of onset, and genetic closeness to me.

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  • Papillon1
    Papillon1 Member Posts: 308
    edited April 2014

    grandma was 58 and mum was 52. Both then went into remission for 10 and 12 years respectively before it metastasized and finally lead to their death. Mum is still with us, but it's in her brain, liver, lungs and bones. Time is precious.

    I am just wondering if those with a family history of breast cancer always show the same type of cancer within their families....

    I agree I am most likely not BRCA. They said 2% chance of it being positive. As it is a very expensive test they would prefer to not test. That said, we are pushing for mum to be tested just in a case. We have lots of girls in our family. But even if it comes back negative I know it doesn't mean there is no genetic links to the breast cancer. I know BRCA is only in 5% or so of cases.

    The genetic people I met with concluded there is a familial tendancy towards breastcacners for us. It pops up on my dads side too in a few generations, not every generation, but evident a few times but in 60s.  All the genetic consultations didn't take types of breast cancer into  account.hence my question on types of breast cancer....can those with a clear genetic pattern of breastcacners sometimes change type of cancer between between geenrations...thanks for your answer divecat.

    Maybe if a family is more "prone" to bc due to genetic and / or environmental factors it may make them more prone to all types of cancers..

    You are right though, there is so much they still need to learn about breast cancer.

    For me 1 in 4 is too high. I want to take action now to protect myself and my family. But I need to be sure a doctor won't turn around in future and say "oh no, there is no chance it's hereditary for you, your mother and grandma had different types of cancer...what a waste of time your operation was.."... I just want to be sure. But in a world of uncertain science I quess there are no certainties...

    And this is all written without me being sure what type of bc grandma had...

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  • Papillon1
    Papillon1 Member Posts: 308
    edited April 2014

    Oh, not long until your op divecat! Gd luck xx

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