Circulating Cell-Free DNA As A Blood Biomarker In Monitoring Response To Chemotherapy In Breast Cancer

Abstract

Background: Cancer incidence and its related mortality is on the rise and is currently the second leading cause of death globally. Breast cancer has a broad impact in the world, with an estimated 20,996 new diagnoses in 2018 alone. Evidence regarding the accuracy and effectiveness of existing modalities such as magnetic resonance imaging (MRI), computed tomography (CT), bone scintigraphy, chemotherapy and radiation therapy, etc., to evaluate and monitor response to breast cancer treatment is limited. Moreover, such modalities are expensive for patients, and frequently exposes them to radiations which affect their health status. There is, therefore, the need for research into alternative predictive biomarkers that can be used to determine or monitor the effectiveness of breast cancer treatment in resource-limited countries like Ghana without exposing patients to radiation. Circulating cell-free DNA “(cfDNA) is produced at elevated levels in cancer patients than in apparently healthy individuals. Assessing cfDNA as a blood biomarker may be useful in monitoring response to treatment especially chemotherapy in breast cancer since chemotherapy is the primary treatment for breast cancer. Aim: The study sought to assess circulating cell-free DNA (cfDNA) as a blood biomarker for monitoring response to chemotherapy in breast cancer patients. Methodology: The study involved 64 females consisting of a test group of 32 breast cancer patients and a control group of 32 apparently healthy controls Venous blood samples were taken at two time points, one before the commencement of chemotherapy and the other after the 3rd cycle of chemotherapy. Venous blood samples were also taken from the apparently healthy controls as well. ALU “species 115 and 247 levels in serum were measured in both the test and control groups. Body Mass Index (BMI) and Waist to Hip Ratio (WHR) of the participants were also assessed. Results: ALU “species 115 and 247 levels in serum were elevated in breast cancer patients than the controls (p-value 0.028 and < 0.001). Circulating cell-free DNA integrity was also higher in the breast cancer patients than the controls. The concentrations of ALU 115 and 247 significantly decreased after the 3rd cycle of chemotherapy in the breast cancer patients unlike the circulating cell-free DNA” integrity which increased. The concentrations of both ALU115 and 247 also decreased after the 3rd cycle of chemotherapy among the tumour grades, stages, molecular and histopathological subtypes of the breast cancer patients. Conclusion: Serum “concentration of circulating cell-free DNA was affected by chemotherapy and may be used as a vague biomarker in monitoring response to chemotherapy in breast cancer.