There are 2 well known breast cancer related genes BRCA1 and BRCA2.
Mutations in these tend to give you a high probability of developing breast, ovarian or bowel cancer 85%
There is an increased incidence of this in people with Ashkenazi Jewish background.
But there is a certain risk without a genetic predisposition too.
You can be tested for this see here
http://www.cancerhelp.org.uk/help/default.asp? page=5689#who
There is particular interest if someone in your familly was very young and had it or had ovarian cancer or if it was a man that had it.