Clinical relevance of double heterozygosity revealed by next-generation sequencing of homologous recombination repair pathway genes in South African breast cancer patients.

Purpose: Genetically predisposed breast cancer (BC) patients represent a minor but clinically meaningful subgroup of the disease, with 25% of all cases associated with actionable variants in BRCA1/2. Diagnostic implementation of next-generation sequencing (NGS) resulted in the rare identification of BC patients with double heterozygosity for deleterious variants in genes partaking in homologous recombination repair of DNA. As clinical heterogeneity poses challenges for genetic counseling, this study focused on the occurrence and clinical relevance of double heterozygous BC in South Africa.

Navigating the genetic landscape of breast cancer in South Africa amidst a developing healthcare system.

Breast cancer is a significant global health issue as it represents the leading cause of death in women worldwide. In 2021, the World Health Organization established the Global Breast Cancer Initiative framework with the aim to reduce the breast cancer mortality rate by the year 2040. In countries with developing healthcare systems, such as South Africa, the implementation of first-world technologies has been slow.

Pathology-supported genetic testing for the application of breast cancer pharmacodiagnostics: family counselling, lifestyle adjustments and change of medication.

Background: Pathology-supported genetic testing (PSGT) enables transitioning of risk stratification from the study population to the individual.

Research Design And Methods: We provide an overview of the translational research performed in postmenopausal breast cancer patients at increased risk of osteoporosis due to aromatase inhibitor therapy, as the indication for referral. Both tumor histopathology and blood biochemistry levels were assessed to identify actionable disease pathways using whole exome sequencing (WES).

Implementation of multigene panel testing for breast and ovarian cancer in South Africa: A step towards excellence in oncology for the public sector.

Translation of genomic knowledge into public health benefits requires the implementation of evidence-based recommendations in clinical practice. In this study, we moved beyond susceptibility testing in breast and ovarian cancer patients to explore the application of pharmacogenetics across multiple genes participating in homologous recombination DNA damage repair. This involved the utilisation of next-generation sequencing (NGS) at the intersection of research and service delivery for development of a comprehensive genetic testing platform in South Africa.

Prevalence of Clinically Relevant Germline Variants in a Large Unselected South African Breast and Ovarian Cancer Cohort: A Public Sector Experience.

Breast cancer is a multifaceted disease that currently represents a leading cause of death in women worldwide. Over the past two decades (1998-2020), the National Health Laboratory Service's Human Genetics Laboratory in central South Africa screened more than 2,974 breast and/or ovarian cancer patients for abnormalities characteristic of the widely known familial breast cancer genes, Breast Cancer gene 1 () and Breast Cancer gene 2 () Patients were stratified according to the presence of family history, age at onset, stage of the disease, ethnicity and mutation status relative to . Collectively, 481 actionable (likely-to pathogenic) variants were detected in this cohort among the different ethnic/racial groups.

Pioneering Point-Of-Care Testing for Integration of Germline and Tumor Genetics in Breast Cancer Risk Management: A Vision for the Future of Translational Pharmacogenomics.

Research performed in South African (SA) breast, ovarian and prostate cancer patients resulted in the development of a rapid BRCA point-of-care (POC) assay designed as a time- and cost-effective alternative to laboratory-based technologies currently used for first-tier germline DNA testing. In this study the performance of the new assay was evaluated for use on a portable screening device (ParaDNA), with the long-term goal to enable rollout at POC as an inventive step to meet the World Health Organization's sustainable development goals for Africa. DNA samples for germline testing were obtained retrospectively from 50 patients with early-stage hormone receptor-positive breast cancer referred for genomic tumor profiling (MammaPrint).

Mutations in BRCA-related breast and ovarian cancer in the South African Indian population: A descriptive study.

Knowledge of the genetic landscape of a specific population group is vital for population-specific diagnosis and treatment of familial breast cancer. Although BRCA-related diagnostic testing has long been implemented in South Africa, the genotyping approach previously failed for the SA Indian population as it was based on other SA population groups. Because this population is uniquely admixed, the lack of population-specific data resulted in the implementation of comprehensive mutation screens for BRCA1/2.

Globally Rare Variants With Founder Haplotypes in the South African Population: Implications for Point-of-Care Testing Based on a Single-Institution Next-Generation Sequencing Study.

Breast cancer patients historically benefitted from population-based genetic research performed in South Africa, which led to the development of founder-based diagnostic tests. With the advent of next-generation sequencing (NGS) technologies, the clinical utility of limited, targeted genetic assays were questioned. The study focused on mining NGS data obtained from an extensive single-institution NGS series (n=763).

The contribution of large genomic rearrangements in BRCA1 and BRCA2 to South African familial breast cancer.

Background: Pathogenic variants that occur in the familial breast cancer genes (BRCA1/2) lead to truncated ineffective proteins in the majority of cases. These variants are mostly represented by small deletions/insertions, nonsense- and splice-site variants, although some larger pathogenic rearrangements occur. Currently, their contribution to familial breast cancer (BC) and ovarian cancer (OVC) in South Africa (SA) is unknown.

BRCA1 mutations in South African breast and/or ovarian cancer families: evidence of a novel founder mutation in Afrikaner families.

Germ-line mutations within BRCA1 are responsible for different proportions of inherited susceptibility to breast/ovarian cancer, and the spectrum of mutations within this gene is often unique to certain populations. At this time, there have been no reports regarding the role of BRCA1 in South African breast and/or ovarian cancer families. We therefore screened 90 South African breast/ovarian cancer families for BRCA1 mutations by means of PCR-based mutation detection assays.