Question about family hx

first degree relatives (mother, daughter, or sister) count the most as their DNA is closest to yours.  Second degree relatives (grandmother, aunt, cousin) also count, but not as much, as their DNA is not as close genetically. (hope that makes sense) I mentioned all the females, but the male counterparts count just as much. As BLinthedses mentioned, age less than 45 at diagnosis also makes a big difference. Your grandmother having bc at age 40 would definitely be of concern and count towards your family history. My mom had bc; but my great-grandmother had bilateral bc in her 40's and all my docs are always very interested in that as well.

Anne 

Sorry to add confusion, but on MO told me that my great-aunt(my mother's mother's sister) was significant for me. It didn't change my treatment or lead to any additional tests. I had bialteral cancer & some say there is more of a genetic link. I was never tested for BRCA. My only living child is a son(with ASD). I think I would have pushed for the test if I had a daughter.

My breast team considers everything.  I don't have sisters.  My maternal grandmother had BC and a mastectomy, my maternal aunt had a double mastectomy and thyroid cancer at the same time. Another maternal aunt had bone cancer. My mom has had multiple lumpectomies and had an ovarian cancer scare and a radical hyster in her 30s.  On father's side, his mom died from ovarian cancer. None of them smoked or drank. They all breast fed and had healthy lifestyles, growing up in the mountains away from a lot of stress, pollution, etc.  Now, they all had cancer in their 60s.  I know the stats say less than 45 is the significant factor, but I think 60s is young to have this kind of disease. 80s I would understand. 

Things run in families, like heart disease and diabetes.  Doesn't mean you're gonna have it, but if it's there, it is typically noted in your medical records and something you should factor into your lifestyle.  Goodness, they ask all sorts of family questions - you know the long list of 30 things including glaucoma, arthritis, and other typically non lifethreatening things.  Well, cancer runs in my family so I think that is important to note and take into account.  if the insurance companies care, shouldn't we? ;-)   Thinking about my family history has also kept me away from bad behaviors like smoking, and I eat healthy and stay in good shape. I am fighting the urge to slide into middle age as I see many of my friends doing now.  I go to all of my doctors regularly and stay vigilant.  I started having huge uteran fibroids and bad pap smears so I had a hyster and got rid of it all instead of waiting around to see what might happen. I guess considering my family history has led to a strong preventitive medicine approach. 

So my personal opinion (just me alone) is to say if it's not mom or sister (if I had one) then the odds are really low  - to me that wouldn't be smart based on watching second degree relatives die from breast, ovarian and bone cancer in their 60s.  Again, just my personal opinion and the way I prefer to live - if some type of cancer ever strikes, I will be happy with myself knowing that I did all I could.