Although harmful mutations in BRCA1 and BRCA2 are responsible for the disease in nearly half of families with multiple cases of breast cancer and up to 90 percent of families with both breast and ovarian cancer, mutations in a number of other genes have been associated with increased risks of breast and/or ovarian cancers. Most mutations in these other genes are associated with smaller increases in breast cancer risk than are seen with mutations in BRCA1 and BRCA2. However, researchers recently reported that inherited mutations in the PALB2 gene are associated with a risk of breast cancer nearly as high as that associated with inherited BRCA1 and BRCA2 mutations. We also test the other 12 genes in the in the breast cancer panel.
The BRCA 1/2 test includes 13 other genes associated with Breast Cancer
ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, NBN, NF1, PALB2, PPM1D, PTEN, RAD51C, STK11, TP53
If your predictive genetic test result is positive, it means you have a faulty gene that raises your risk of developing cancer. It doesn’t mean you are guaranteed to get cancer – your genes only partly influence your future health risks. Other factors, such as your medical history, lifestyle and your environment, also play a role. If you have one of the faulty BRCA genes, there is a 50% chance you will pass this on to any children you have and a 50% chance that each of your siblings also has it.
The faulty BRCA genes affect around 1 in every 400 people, but people of Ashkenazi Jewish descent are at a much higher risk (as many as 1 in 40 may carry the faulty gene).
The average lifetime risk of breast cancer for women is about 12%. That’s 1 out of 9 women. For women who have a BRCA1 or BRCA2 mutation, the risk of developing breast cancer in a lifetime is between 40% and 85% – about three to seven times greater than that of a woman who does not have the mutation. The lifetime risk of ovarian cancer is significantly elevated as well: 16% to 44%, versus just under 2% for the general population. Men with BRCA abnormalities are considered to have a higher lifetime risk of male breast cancer, especially if the BRCA2 gene is affected. One study found that men with a BRCA2 mutation have a 7% lifetime risk of developing breast cancer. They are also at increased risk of developing prostate cancer.
Advantages of having the test
- A positive result means you can take steps to manage your risk of developing cancer– you can make certain lifestyle changes to lower your risk, have regular screening and have preventative treatment like surgery.
- Knowing the result may reduce any stress and anxietythat comes from not knowing. Most of the time the result will be negative.
Disadvantages of having the test
- The results of some genetic tests are inconclusive– doctors may identify a variation in a gene, but may not know what effect it may have.
- A positive result may cause permanent anxiety– some people would rather not know about their risk and only want to be told if they actually develop cancer.
This genetic has developed a next-generation sequencing-based test for identifying hereditary cancer susceptibility mutations. The test uses advanced next-generation sequencing (SMSEQTM) targeting 15 genes with a high-degree of analytical sensitivity and specificity. Validation using industry standard methods yielded an accuracy of 99.99%. The genetic panel includes 15 genes reported in the literature as being associated with increased risk for breast cancer and possibly other cancer/tumour types.
The 15 genes tested include:
ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, NBN, NF1,
PALB2, PPM1D, PTEN, RAD51C, STK11, TP53
Certain mutations in certain genes are associated with an increased risk for cancers and/or hereditary syndromes. These mutations are associated with the potential to alter medical intervention. A pathogenic variant directly contributes to the development of cancer. The variant has strong lines of evidence that associates it with significantly increased cancer risk and necessary clinical action.
A likely pathogenic variant is very likely to contribute to the development of cancer. The variant has fewer strong lines of evidence that associates it with significantly increased cancer risk.
A likely benign variant is not expected to have a major effect on cancer. However, additional evidence is needed to confirm this assertion.
All people carry genetic variants inherited from their parents. A variant can be used to describe a change in a DNA sequence that may be pathogenic, likely pathogenic, unknown significance, likely benign, or benign. Most variants do not cause an increase in the risk of cancer or other disease. The classification and interpretation of all variants identified in the test reflects the current state of scientific and medical understanding at the time the report is generated. Variants are classified by pathogenicity by taking into account the reported variant, and the allelic frequencies from population studies and clinical databases. A positive test result indicates that an individual has inherited a pathogenic mutation in specific genes and therefore, has an increased risk of developing certain cancers. It is important to understand that a positive test result does not necessarily mean that the individual will actually develop cancer over their lifetime. Some individuals who inherit pathogenic mutations will never develop the associated cancer(s). A negative test result indicates that an individual has not inherited a pathogenic mutation in any of the genes tested, but does not eliminate the lifetime risk of developing certain cancers.
A variant of uncertain significance does not have enough information at this time to support a more definitive classification. There is insufficient evidence to determine if the variant is associated with increased cancer risk.
A benign variant has strong lines of evidence that does not associate it with an increased cancer risk.