How do I know if my family history is significant?

In evaluating a family history for a cancer genetic syndrome, it is important to look at how many relatives have cancer, how many relatives have cancer at an early age, and how many of these individuals have had more than one primary cancer. The following examples of significant family histories strongly suggest that a gene mutation is passed on from a parent to a child, and that gene mutation predisposes individuals to cancer. Many of the family histories that we see in our clinic are not as significant as these examples but still could represent a cancer genetic syndrome. Family histories may provide limited information because of few relatives or adoption.

Is there breast cancer in your family?

This family has women with breast cancer in two generations and the age of cancer diagnosis is early, before 50 years, suggesting the possibility of a gene mutation in the family. Even though the male in the family was not diagnosed with breast cancer, it is possible he inherited a gene mutation for breast cancer that could be passed on to his daughter.

Is there colon cancer in your family?

Because of the early age of diagnosis and the number of individuals with colon cancer, this family strongly suggests a genetic component for cancer with autosomal dominant inheritance. The type of colon cancer (related to the number of polyps) would identify the suspected gene in this family.

Is there ovarian cancer in the family?

The occurrence of breast cancer suggests that this family represents a hereditary breast/ovarian cancer syndrome. Note that the male in this family does not have cancer but appears to have passed on a gene mutation for cancer to his daughter who was diagnosed with ovarian cancer. This is an example of why the family history of both parents must be evaluated for cancer.