A person may worry if their aunt has breast cancer, as it may indicate a family history of the disease. However, while there is an associated risk with first-degree family members, such as mothers, brothers, fathers, and sisters having breast cancer, second-degree family members, such as grandmothers and aunts, have a slightly decreased risk than with first-degree family members.

Certain genes, such as the mutated BRCA 1 and 2 genes, may run in families. A person with this gene may have a higher risk of developing breast cancer. This altered gene can lead to tumors and uncontrollable cell growth.

A BRCA gene can multiply the risk of a person developing breast cancer, including:

  • more than 60% of women with the gene will go on to develop breast cancer, compared to 13% of women of the general population without the gene
  • about 0.2% to 1.2% of men with a harmful inherited BRCA1 gene change, and 1.8% to 7.1% with the BRCA2 altered gene, will go on to develop breast cancer before the age of 70
  • 39% to 58% of women with a harmful inherited BRCA1 gene will go on to develop ovarian cancer, and 13% to 29% with the BRCA2 gene

If there are multiple generations of family members receiving a diagnosis of breast cancer, a person can speak with their doctor about testing for the mutated gene. A gene specialist, or a specialist genetics service, can help with finding out what inherited genes a person has.

Other genes that can cause breast cancer include the abnormal CHEK2 gene, which can double the risk of developing breast cancer.

It is always important to speak with a doctor or healthcare professional about receiving a mammogram screening, particularly if there is a family history of breast cancer. It is also important to recognize that there can be other hereditary reasons for breast cancer outside BRCA or CHEK, which is why getting a panel of testing may be indicated, which tests for many more genes.