Research points to genetic faults brought to SA by three Dutch couples.
If you are an Afrikaner or Jewish woman of Ashkenazi ancestry you could be at higher risk of developing breast cancer.
Researchers from the University of Pretoria have discovered these women carry mutations in a gene known as BRCA, which make them susceptible to types of cancer that collectively kill about 600?000 women worldwide every year.
Although scientists have known for years that women of Dutch and Jewish ancestry are susceptible to these mutations, Lizette Jansen van Rensburg, a professor of genetics at the University of Pretoria, says there is something unique in three key faulty mutations, in particular in South African women of Afrikaner ancestry.
She explained: “Collectively these three faults account for 94% of BRCA faults that are detected in Afrikaner breast cancer families.
“Because so many of the Afrikaner families had one of the three unique BRCA faults, we investigated the origin of the faults, and discovered that each fault (two in BRCA1 and one in BRCA2) could be traced to three European couples (who came to South Africa in the late 1600s to early 1700s). Although they had specific surnames, current families do not necessarily have the same surnames,” she said.
While the genetic mutation is more common among Caucasian women, other ethnic groups are not safe from it. Experts recommend that any person who has two or three family members who have been diagnosed with breast or ovarian cancer undergo genetic testing.
Several tests can be done to determine if one is genetically predisposed to developing breast or ovarian cancer. If the results are positive, one could be continuously monitored to detect breast cancer early or one could undergo a mastectomy, which will reduce the risk of breast cancer by 90%.
But associate professor of surgery at the University of Stellenbosch Justus Apffelstaedt said having a double mastectomy was a life-changing step and should not be taken lightly. “Once the breasts are removed, the woman would not be able to breast-feed when she decides to have a child,” he said.
Actress Angelina Jolie revealed this week that she had a double mastectomy because she was found to have a faulty BRCA gene.
Many praised her for raising awareness about cancer risk and genetic testing. But some local experts felt the hype surrounding Jolie’s decision may create an impression that mastectomies are the only way patients can escape cancer.
Sue Janse van Rensburg, the CEO of Cansa agreed, saying: “We don’t promote this life-changing procedure without ensuring the patient has access to a comprehensive health team in respect of counselling and support after surgery – this includes consulting her loved ones before taking this decision.”
Janse van Rensburg also said removing one’s breasts doesn’t guarantee a cancer-free future.
“It must be understood that although it may reduce your risk by up to 90%, you still have a 10% chance of developing it after a mastectomy, as you can’t remove all breast tissue during surgery,” she said.
Breast cancer is the most common cancer in South African women. National Cancer Registry figures show that breast cancer is also the number one cancer among women of all population groups except black women, where it comes in second after cervical cancer.
But it is genetically inherited in only 5% to 10% of cases.
How do genes cause cancer?
» BRCA1 and BRCA2 are human genes which belong to a class of genes known as tumor suppressors. Mutations, or faults, in these genes have been linked to hereditary breast and ovarian cancer.
» Genetic mutation in BRCA1 and BRCA2 is most common among white people and those of Ashkenazi Jewish descent
» Experts recommend that man or woman who has had two or more family members diagnosed with breast or ovarian cancer should conside undergoing genetic testing at the age of 20
» The test costs about R1600 and can be done at private or public hospitals
» If a genetic mutation is found, several options are available to help the patient manage their cancer risk – including mastectomy.
» A positive test result generally indicates that a patient has inherited a known harmful mutation in BRCA1 or BRCA2 and has an increased risk of developing certain cancers.
Source: US National Cancer Institute