Tracking the history of circulating nucleic acids for cancer research in Brazil: A systematic review

Introduction: Circulating nucleic acids can be obtainedby minimally invasive procedures based on liquid biopsy,which has emerged as a promising area of investigation forscreening and monitoring cancer treatment. Currently, testsbased on circulating nucleic acid analysis, specifically cellfreeDNA (cfDNA), are commercially available for diagnosticand prognostic investigation of a number of neoplasms. Objective:To describe the research on circulating nucleic acidmarkers for cancer prospecting in Brazil, since this area hasadvanced rapidly in recent years. Methods: In this systematicreview, we surveyed Brazilian publications in cancer researchfocused on cfDNA and cfRNA present in different fluids. BothMEDLINE-PUBMED and EMBASE databases were inspectedusing terms such as “circulating nucleic acids”, “cancer”, and“Brazil”. Results: The search returned 326 articles, in which28 Brazilian translational studies were eligible. Differentmethodologies were reported for different types of cancer,in which cfDNA from plasma was the most investigatedbiological material. Molecular investigations included quantification,somatic mutation, RNA expression, genotyping,microsatellites, blood protein interaction, and methylation.Discrepancies in the regional distribution of the studies werealso observed. Conclusion: Studies on circulating nucleic acidmarkers have advanced significantly in the oncology field,but many others are needed to better address the clinicalpractice in Brazil.