Evaluation of free circulating DNA (cfDNA) concentration in liquid biopsy samples from patients with non-small cell lung cancer and association with clinical parameters and disease outcome

Abstract

Introduction: Patients with non-small cell lung cancer (NSCLC) are constantly being submitted to re-biopsies for clinical management and investigation of molecular changes in order to determinate the best treatment and monitoring. However, conventional biopsies are highly invasive. The liquid biopsy is a sample of minimally invasive collection, coming from body fluids. This liquid biopsy samples contain free circulating DNA ou cfDNA, and their concentrations appear to correlate with disease staging and clinical outcome. Due to the great importance of monitoring the evolution of the disease, the analysis of the concentrations of cfDNA shows a potential clinical application and could help in the monitoring of the treatment and, possibly, the early detection of the disease by minimally invasive method. Objective: To assess the concentrations of cfDNA in liquid biopsy samples from patients with NSCLC and to correlate with the clinical parameters of the disease, overall survival and outcome. Materials and methods: The liquid biopsy of 50 NSCLC patients will be evaluated, which will be submitted to the extraction of cfDNA from the plasma by means of the MagMax Cell-free cfDNA Isolation Kit, and the samples will be quantified by fluorometry, spectrophotometry and evaluated by TapeStation. Analysis of concentration obtained with disease staging will be performed by the Mann-Whitney and Kruskal-Wallis tests and with overall survival and outcome using the Keplan-Meier curves and the association will be evaluated by log-rank test, all with significance level of 5% (p d 0.05). Expected results: Measurement of cfDNA concentrations in liquid biopsy sampes from patients with adenocarcinoma may be useful to identify patients with a possible unfavorable outcome, early disease recurrence and progression of the disease. The detection of cfDNA can be used as a biomarker of worse prognosis and as a biomarker for monitoring the disease.