Are genes a factor?

My mom, age 71,  just passed away three weeks ago from metaplastic spindle cell carcinoma of the breast, a rare and very malignant type of cancer, I'm finding out. I also found out, that about ten years ago, my mom had a second cousin, (younger than 40)  that had the same type cancer. The women in the cousin's side of the family have almost all died from breast cancer, but my mom is the first one from her side(that we have knowledge of) and I'm wondering if there is a genetic factor and should my sister, and nieces and I be concerned?

[japdip]

Genetics certainly do matter and not only where breast cancer is concerned. With a family history you all should be extra vigilant and perhaps have a discussion with a Genetisist regarding genetic testing. You might talk this over with your Primary Care Physician.