Is cancer genetic?

If both my mother and my sister had breast is there a
risk for me to develop some form of cancer as well?

No, cancer is not genetic, but sometimes the genes that increase your
risk are. For example, BRCA1 and BRCA2 genes that are the cause of some
(but not all) cases of breast cancer. This is the reason why, if you are
a new patient, a doctor will ask for your family medical history. Heredity
can be a risk for cancer as it is for many other things.