While most cancers are NOT inherited, about 10 to 15% are caused by a single gene mutation passed through the family. Determining if a genetic susceptibility is contributing to a personal and/or family history of cancer may assist in medical management of those risks. This knowledge may also clarify the cancer risks that relatives face. Some relatives may be reassured by learning that they have not inherited a familial tendency and therefore do not require intensive screening, and cannot pass the familial tendency to their children.
When Should I Suspect A Breast Cancer May Be Hereditary?
When breast cancer is caused by a single gene mutation passed through the family you may see
Breast cancer diagnosed at an early age (e.g. under 50)
Multiple family members (blood relatives) with cancer
Certain combinations of related cancers (breast and ovary, sarcoma, adrenocortical carcinoma
and childhood cancers) in an individual or blood relatives
An individual with two or more primary cancers
Family history of breast cancer, gastrointestinal malignancies, and thyroid disease, both benign and malignant
- Specific ancestry (for example Ashkenazi Jews have an increased frequency (1/40) of carrying a mutation in one of two genes that predispose to hereditary breast and ovarian cancer)
Specific consideration of the possibility of hereditary breast and ovarian cancer syndrome (BRAC1 or BRCA2 genes) should be given with any of the following:
In Ashkenazi Jewish families:
- diagnosed < age 55
- any age if family history of breast and/or ovarian cancer
Ovarian, fallopian or primary peritoneal cancer:
- personal or family history, any age
Any personal history of breast cancer:
Any family history of breast cancer (biological relatives on the same side of the family. This includes paternal relatives)
both breast and ovarian cancer among first- and second-degree relatives
a first-degree relative with bilateral breast cancer
2 or more first- or second-degree relatives with ovarian cancer regardless of age at diagnosis
a first- or second-degree relative with both breast and ovarian cancer at any age
history of breast cancer in a male relative
Any family history of breast & ovarian cancer:
- both cancers in any female relative
- one of each cancer in 2 close biological relatives on the same side of the family, diagnosed at any age
Any family history of ovarian, fallopian tube or primary peritoneal cancer:
These features are only guidelines for assessing the risk for hereditary cancers. When these factors create a pattern in the family history that is recognizable to your physician or genetic counselor, it may indicate a hereditary risk for cancer. Breast, ovarian and colon cancers are the most common types of cancer that have been linked to specific genes.
Is There A Test To Determine If Breast Cancer Is Hereditary?
The family history and cancer types in a family are used to determine the likelihood of a hereditary cancer syndrome and, if a syndrome is suspected, which gene(s) should be analyzed. Genetic testing is available for BRCA1 and BRCA2 – the two most common genes known to be associated with hereditary breast and ovarian cancer. Everyone, men as well as women, has these genes. When an individual carries an alteration in one of these genes, the chances of developing breast or ovarian cancer are significantly higher than average.
Genetic testing is a method of analyzing an individual’s genes for mutations and is available as a blood test for the BRCA1 and BRCA2 genes. It is generally most informative if a relative who has had cancer is tested first, to determine if an identifiable gene mutation exists in the family. If a mutation is identified in an affected relative, at-risk family members may elect to be tested for the familial mutation; those testing positive have a significantly increased risk of developing cancer, while those relatives testing negative may be told that they have the general population risk of developing cancer.
What should I do now?
Please use this section as background education. It is not a substitute for a clinical visit to our Center or discussion of a possible hereditary condition with your physician.
Take the next 10 minutes to fill out the online MyGenerations
for an initial evaluation of your risk of breast cancer.
Make an appointment with your physician to discuss your risk of cancer.
Make an appointment with the Center for Medical Genetics by calling 847.570.1029.
E-mail this page to a friend or loved one that may be at risk.