Some of the frequently asked questions that we receive about more than one diagnosis in one family are:
How many genes can genetic testing test?
Although genetic testing for breast cancer has been around for over three decades, it is constantly evolving. Today, we have panel-testing for no less than 84 genes available.
Should you have genetic testing?
While you cannot change your genetics or family history of breast cancer, knowing that you are at a higher risk can help with creating an early detection plan to detect breast cancer in its earliest stages, while it is still localized (there is no sign that the cancer has spread outside of the breast), and easier to treat.
Some people with a family history of breast cancer may choose to undergo genetic counselling and genetic testing to see if they have inherited genes that increase the risk of the disease. It is also advisable to maintain an accurate family medical history to determine if there is a significant family history of breast cancer or other illnesses.
Once you’ve had the test, what happens then?
Most individuals choose (with their medical team) what to do. Below are the typical actions:
- Age 0 – 18: Usually no action, however, additional screening can be offered in specific cases.
- Age 18 – 30: Surveillance: Annual breast imaging usually includes MRI OR risk reduction surgery, and ovarian cancer screening.
- Age 30 – 70: Active surgical risk management: Risk reduction mastectomies followed a couple of years later by risk-reduction salpingo- oophorectomy depending on the mutation and risks that it infers.
- Age 70+: Clinical management.
In addition to the well-known BRCA1 and 2 tests, what other tests are commonly done?
- PALB2 – After BRCA1 and BRCA2, PALB2 is currently the third most prevalent breast cancer gene. PALB2 is short for “Partner And Localizer of BRCA2.” In other words, it works in partnership with the BRCA2 gene to repair DNA damage and thereby prevent breast cancer from developing. An estimated 35% of women with a mutated PALB2 gene will develop breast cancer by age 70.
- CHEK2 – “Checkpoint Kinase 2,” or CHEK2, creates a protein that helps suppress tumour growth. Having a mutated CHEK2 gene doubles the risk of breast cancer in women. In men, it makes male breast cancer 10 times more likely to occur.
- CDH1 – CDH1, or “CaDHerin 1,” is a tumour suppression gene that helps groups of cells stick together to form organized tissues. A mutation in the CDH1 gene can increase the risk of forming lobular breast cancer, or cancer that begins in the breast’s milk-producing lobules. Since the gene normally helps cells stick together, a mutation can also make it easier for individual cancer cells to break off from a breast tumor and metastasize, or spread to other parts of the body.
- PTEN – The “Phosphatase and TENsin homolog” (PTEN) gene helps prevent tumour growth by controlling the rate of cell division. It also causes damaged cells to self-destruct before they can become cancerous. Like CDH1, PTEN also plays a role in helping cells stick together, which can help prevent cancer from spreading.
- STK11 – “Serine/Threonine Kinase 11” is another tumor suppressor. STK11 gene mutations cause Peutz-Jeghers syndrome. Peutz-Jeghers syndrome carries an increased risk for multiple types of cancer, including breast cancer.
- TP53 – Also known as P53 (and nicknamed the “guardian of the genome”), “Tumor Protein p53” recognizes when a cell’s DNA has been damaged. It then activates a DNA repair gene (like BRCA1) or causes the cell to self-destruct. If TP53 is mutated, the damaged DNA won’t be repaired and the cell will live on, perhaps becoming a cancer cell. Though some TP53 mutations are inherited, most of them occur during a person’s lifetime and are only found in cells that become cancerous.