07 November 2022
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Story André Damons
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Photo André Damons
Dr Nerina van der Merwe is a principal medical scientist in the Division of Human Genetics within the Faculty of Health Sciences and the National Health Laboratory Service (NHLS), who has been performing research on various familial breast and ovarian cancer genes throughout the years.
Researchers in the University of the Free State (UFS) Division of Human Genetics believe the implementation of a new diagnostic test for familial breast and ovarian cancer – using new technology based on rapid point-of-care (POC) testing – will reach more communities and hopefully contribute to saving more lives.
“We were approached by Prof Kotze, who is also very passionate about cancer research. She and her team, together with a company in the United Kingdom, have been working on designing a POC assay for this new technology, based on our research results. We became involved, as we are currently the state referral centre for familial breast and ovarian cancer in the country and have screened more than 3 000 patients diagnostically up to now. With the use of our research results and access to positive controls, we are in a position to assist with the validation and potential implementation of this technology in the future,” says Dr Van der Merwe.
Years of research
According to her, this new technology – once it is validated as a diagnostic genetic test – is the future of familial breast and ovarian cancer testing in South Africa when performed in conjunction with genetic counselling. The robustness of the assay and user-friendly practical method makes it extremely suitable for use in rural clinics, thereby eliminating the need for expensive laboratory equipment. By performing the test at the community clinic, patients no longer have to be transported to tertiary hospitals for genetic testing, and more patients and related family members who are unaware that they have inherited a disease-causing change in high-risk cancer genes such as BRCA1 or BRCA2, will be reached.
Dr Van der Merwe has been involved with genetic research on familial breast and ovarian cancer since 1995 and says this is the outcome of nearly 30 years of South African-specific cancer research. She was appointed with the main goal of determining the range and contribution of genetic changes in these two genes to our population. Her work, in collaboration with Prof Lizette van Rensburg from the University of Pretoria, identified the first South African-specific variants, which proved to represent South African-unique recurrent, or founder variants found in African and Afrikaner populations. Gradually, the number of founder variants unique to our population increased to a total of six, says Dr Van der Merwe. The presence of these founder variants in our population is ideal for the implementation of rapid POC testing, as these variants are common in affected patients and justify being screened first, before moving onward to more expensive diagnostic testing.
She is extremely excited that the progress being made in the field will not only benefit the patient, but also unaffected at-risk family members. According to her, implementation of this new technology has various benefits; not only is it cheap and robust, but the results are available within 90 minutes. Another benefit is that the test will be validated using saliva or a buccal swab, which is less invasive than taking a blood sample. By performing genetic counselling while the test is running, patients and family members will have the opportunity to ask questions about genetic testing and cancer, which will simultaneously increase community awareness. By talking during a face-to-face consultation, the counsellor can ensure that the patient and related family members understand the value of the test. This will eventually result in an increase in the currently low uptake of genetic testing in related at-risk family members, as this cancer type is inherited.
Benefits of POC
“The majority of the patients we are currently testing are already affected. Should a patient test positive, it might assist in their cancer treatment. We, however, need to screen the related family members to identify who is at an increased risk, but currently, this is not the case. So, I think by taking the test to the patients, that is where the benefit would be, as patients are often accompanied to the clinics by their family members. This will provide an opportunity to inform them, as patients often do not discuss their diagnosis and test results with family members. This is evident in patients receiving a positive test result for an inherited disease, but who are not even aware of a family history for these cancer types. This applies especially to African communities.”
“The possible impact of such a testing strategy makes me extremely excited, because why are we doing this? We need to warn unaffected related individuals about their risk, which can only be done by testing them. By doing this, we can play a part in the earlier detection or diagnosis of patients, ultimately improving their cancer survival rate.”
Apart from founder testing, Dr Van der Merwe and her team have since broadened their testing regime from screening for BRCA1 and BRCA2 only, to multi-gene panel testing using next-generation-sequencing to include other genes causing these two and other specific cancer types.
Additional Information:
The value of doing genetic testing
Familial breast and ovarian cancer are mainly due to genetic changes in two specific genes, namely BRCA1 and BRCA2, although other genes have also been identified in recent years. These genes mostly have an autosomal dominant inheritance, which means that either parent can pass it on to the children. In the end, each child has a 50% chance of inheriting the genetic disease-causing change or pathogenic variant. These types of tests are extremely valuable for unaffected related family members, as it provides an opportunity to warn people who are not yet affected, such as children or siblings of the patient, about their risk. As survival from breast cancer is dependent on the stage of the tumour at the time of diagnosis, it is critical to know your genetic status. By being tested for the disease-causing variant in your family, you will know whether you are at a higher risk of developing cancer types associated with these pathogenic variants in these genes, or in the case of a negative test result, that your risk is the same as any member of the general population. Additionally, the presence of disease-causing variants means that treatment can be somewhat personalised, making it more effective early on.
Implementation of the POC assay in conjunction with genetic counselling in rural settings will meet the goals set by the World Health Organisation (WHO) for Africa. Their goals for the African continent include, for example, extending health services to currently unreached populations, such as rural settlements, to ensure that no patients are left behind. Other goals entail improving the process of care, and proactively identifying and increasing services to all age cohorts. By performing the POC assay in rural settings, all these goals will be addressed, as the test itself will be more cost-effective (reducing the price of testing from R2 500 to approximately R700, excluding counselling); the waiting period for test results will be shorter, which will cause less anxiety; the test will be taken to the patient, who will receive better care; and finally, cancer awareness in the community will increase, which could result in earlier detection due to patients being aware of their mutation status and receiving better care.