Top five genetic red flags for breast cancer

Red flags are features of the personal or family medical history that suggest a higher than average genetic contribution to cancer. 

Multiple affected relatives with breast cancer or related cancers

The presence of multiple affected relatives suggests a shared genetic or environmental contribution to the cancer in the family. Associated cancers include breast and ovarian, or endometrial and colon, among others. These cancers may be seen together in families with a hereditary syndrome. In general, the greater the number of affected relatives with the same or related cancers, the greater the likelihood of an inherited or shared cause to the cancer. 

See the Genetically related cancers factsheet for more tips on recognizing cancers that can be associated in hereditary conditions.

Early onset cancer

Common, complex disorders that occur at an earlier age than expected are more likely to have a genetic etiology. Pre-menopausal breast cancer suggests an underlying susceptibility. 

Male breast cancer

Breast cancer occurs more commonly in women than men. This difference reflects a variety of factors such as hormonal, developmental, and environmental variables. If breast cancer occurs in a man, however, it is possible that inherited genetic influences have superseded the other factors. When a man does develop breast cancer, it suggests a hereditary susceptibility.

Multiple primaries or bilateral disease

Over time, people are exposed to environmental influences that may cause changes and damage to genes, organs, or body systems. When changes result from genetic risk factors, they are more likely to occur in multiple locations. Bilateral breast cancer, or breast and ovarian cancer in the same person, is most often seen in individuals with a genetic predisposition to cancer.

Ethnic predisposition 

Certain genetic changes are more common in specific ethnic groups due to historical factors affecting entire populations. 1 in 40 individuals of Ashkenazi Jewish ancestry carries a mutation in either the BRCA1 or BRCA2 genes. Specific BRCA1/2 mutations are also clustered among other ethnic groups, including families in the Netherlands, Iceland and Sweden.

See the Cancer risk assessment tool to learn more about red flags and risk assessment.