Cape Town - Between five and 10 percent of people have mutations in the BRCA1 and BRCA2 genes that increase the chances of developing breast cancer by between 50 and 85 percent, Stellenbosch University says.
The university also says that there are founder mutations in the BRCA1 and two genes of most Afrikaner and Ashkenazi Jewish patients with familial breast cancer in South Africa, meaning that a faulty gene occurs at a higher-than-normal rate in affected individuals from these populations due to a communal ancestor carrying the original mutant gene.
Maritha Kotze, of the Stellenbosch Faculty of Medicine and Health Sciences, said that genes can affect not only your risk of getting breast cancer, but are also an important consideration when planning treatment for breast cancer patients.
Kotze said knowing the genetic origin of cancer can improve your treatment outcome for breast cancer and potentially save patients hundreds of thousands of rand.
The cost for mutation tests can range from between R2 000 for known mutations to R12 000 for a full gene screen, and further tests to determine if chemotherapy or other targeted treatment will be useful, can go up to R35 000.
She said women who have not developed cancer are encouraged to go for genetic counselling to determine whether they will benefit from genetic testing.
“Having a gene mutation doesn’t mean you will get the disease. In fact, all of us have at least five to 10 gene mutations with the potential to make us sick. But because of environmental and other clinical and genetic factors, it will never cause any problems,” Kotze said.
She added that genetic counsellors can also be contacted at different academic or private hospitals or a patient can ask their doctor to refer them to a genetic counsellor if concerned about familial risk.
During the counselling session a pre-test assessment is performed to determine the appropriateness of genetic testing in a specific individual and to discuss the potential benefits and limitations of genetic testing.
Post-test counselling will address the implications of a positive or negative test result, the limitations of the specific test procedure, disease penetrance, preventive measures or treatment options.
Hannah Simonds, head of the Division of Radiation Oncology at Tygerberg Hospital, said the molecular make-up of a cancer tumour plays an important role in the treatment of breast cancer.
“Each individual breast cancer has its own unique molecular make-up.
“One of these molecular types is the HER2 breast cancers, which accounts for about 25 percent of all breast cancers. Receptors on the HER2 cell surface help control the healthy growth of breast cells, but when the receptor is faulty it can cause cells to grow uncontrollably, causing HER2-positive breast cancer.”
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Cape Times