IARC 60th Anniversary - 19-21 May 2026
Session : 19/05/26 - Posters
Association between Oxidative Stress and Breast Cancer: A Case-Control Study of Black South African Women
OYIBO A. 1, VENTER G. 1,2, DU PLESSIS C. 1, TALJAARD-KRUGELL C. 3, JOFFE M. 4,5, CUBASCH H. 4,6, RINALDI S. 7, ERASMUS E. 1
1 Biomedical and Molecular Metabolism Research Group, Faculty of Natural and Agricultural Sciences, North-West University,, Potchefstroom, South Africa; 2 Department of Biochemistry, Faculty of Natural and Agricultural Sciences, North-West University, Mahikeng Campus, , Mmabatho, South Africa; 3 Centre of Excellence for Nutrition, North-West University,, Potchefstroom, South Africa; 4 Non-Communicable Diseases Research Division, Wits Health Consortium (PTY) Ltd., , Johannesburg, South Africa; 5 Department of Paediatrics, Faculty of Health Sciences, MRC Developmental Pathways to Health Research Unit, University of Witwatersrand, , Johannesburg, South Africa; 6 Department of Surgery, Faculty of Health Sciences, University of Witwatersrand, Private Bag X2600, Houghton, Johannesburg2041, South Africa, Johannesburg, South Africa; 7 International Agency for Research on Cancer (IARC/WHO), Nutrition and Metabolism Branch, , Lyon, France
Abstract
Background/aim: Breast cancer (BC) is a global epidemiological challenge, with a leading cause of cancer death among females. Over two decades, the incidence of breast cancer cases among South Africans has steadily increased. It is hypothesised that one of the major mechanisms that promote breast cancer is the imbalance between the generation of reactive oxygen species and the antioxidant system of the cells, which results in oxidative stress. Although studies have linked oxidative stress with BC, little is known about how it is associated with black South African women (BSAW). Hence, this study aims to determine the association between oxidative stress and breast cancer in black South African women.
Methods: A total of 398 breast cancer cases and 398 matched control BSAW were enrolled for the South African breast cancer study between 2014 and 2017. The serum from matched cases and controls was used in assessing peroxides as an indication of the level of reactive oxygen species (ROS) and ferric reducing ability of plasma (FRAP) levels by UV-spectrophotometry, while red blood cell samples from matched case-controls were used in assessing reduced and oxidized glutathione (GSH and GSSG) by liquid chromatography-mass spectroscopy (LC-MS/MS). After excluding hormone users, data was analyzed using paired t-tests and association analyses using conditional logistic regression overall and after stratification by menopausal status, BC subtype and BC stage.
Results: Among women not using hormones at time of sampling, FRAP levels were higher in luminal A BC cases (42.87 ± 16.55) vs controls (33.64 ± 12.31) and lower in triple negative BC cases (31.75 ± 11.31) vs controls (35.46 ± 15.20). No significant differences were found in any of the other oxidative stress markers overall or after stratification. Conditional logistic regression analyses revealed no significant association of serum ROS or red blood cell glutathione levels with breast cancer. A positive association was found between FRAP and luminal A BC (OR=1.07 (1.013–1.131) and an inverse association between FRAP and triple negative BC (OR=0.955 (0.913–0.999). These associations were maintained after adjusting for selected confounders (HIV, diabetes, hypertension, smoking, alcohol use, and physical activity) but may require further sensitivity analyses.
Conclusion: Although the study could not confirm any strong association with the selected oxidative stress biomarkers and BC overall, luminal A BC appeared to be moderately associated with increased FRAP and triple negative BC with decreased FRAP levels. Further sensitivity analyses or inclusion of more stable oxidative stress biomarkers (e.g. urinary isoprostanes) may provide more clarity about the association of oxidative stress in BC in BSAW.