Genetic testing for cancer susceptibility is not appropriate for everyone, but it is offered if you have a personal and/or family history of cancer that suggests you may have an increased chance of developing hereditary cancer.
If the genetics provider orders a genetic test for you this is usually done on a small sample of blood or body tissue. If one of your close relatives already had a genetic test for the same disorder it is very important to bring a copy of that lab report to your genetics visit. The time it takes to get results varies depending on the test. Your genetic provider will contact you with your results.
If the results of genetic testing confirm that you have a genetic predisposition to cancer, it’s important to remember that having a gene mutation does not mean you currently have cancer or will definitely develop cancer, only that you have a greater chance than most people. Some people with an inherited cancer predisposition never develop the disease.
There are many things you can do to reduce your chance of developing cancer such as having risk reducing surgery or having regular screenings to detect cancer early.
Your blood relatives (your children, siblings, parents, nieces and nephews, etc.) can also use the information to decide if they want to pursue genetic counseling and testing.
Testing for breast/ovarian cancer genes
The most common breast/ovarian cancer susceptibility genes are called BRCA1 and BRCA2 (Breast Cancer Gene 1 and 2). Scientists believe that about 5% (5 in every 100 cases) of breast cancer are related to an inherited mutation in a cancer susceptibility gene. Both men and women can pass down the BRCA gene mutations to their children.
Mutations in these susceptibility genes are associated with an increased chance for:
- Breast and ovarian cancer
- Other cancers including pancreatic, melanoma and prostate
Women with BRCA mutations:
- Tend to develop breast cancer at younger ages, often before age 50
Men with BRCA mutations:
- Have an increased chance for breast and other cancers
- Chance is not as high as for women
Mutations in other genes can also cause an increased susceptibility to breast and ovarian cancer.
Testing for colon cancer genes
Scientists believe that about 5% (5 in every 100 cases) of colon cancers are related to an inherited mutation in a cancer susceptibility gene. There are several types of inherited susceptibility to colon cancer:
- Most common type of inherited colorectal cancer
- Leads to an increased chance of colorectal, uterine, and other cancers (for example: ovary, stomach, small intestine, urinary tract, etc.)
- Caused by mutations in one of the following genes: MLH1, MSH2, MSH6, PMS2 and EpCam
Familial Adenomatous Polyposis (FAP)
- Another type of hereditary colorectal cancer
- Tendency to develop a large number of polyps (small growths) in the colon and/or rectum, often starting in childhood
- Extremely high chance of developing colorectal cancer before age 40
- Caused by mutations in a gene called the Adenomatous Polyposis Coli (APC) gene
¿Podría haber un riesgo de cáncer en su familia? Aprenda a reconocer las señales del riesgo hereditario de cáncer y cómo proteger su salud y la de sus parientes.