Tumor cells release circulating cell free DNA (cfDNA) into the blood and it is believed that elevation of these cfDNAs in the plasma of patients may be associated with malignancy. Advanced technologies have made it possible to identify specific genetic alterations and to detect rare mutations in a background of wild type sequences from blood samples, known as a non-invasive liquid biopsy. Analysis of blood samples for the presence of circulating tumor cells (CTCs) or cell free circulating tumor DNA (ctDNA) can be performed repeatedly, and might allow real-time monitoring to detect the earliest stages of tumor growth and selection of cancer therapies for treatment resistance in individual patients.
This technical note describes the method development for purification of cfDNA from 200μL-300μL of plasma using Beckman Coulter’s Agencourt RNAdvance Blood kit. Beckman Coulter’s SPRI (Solid Phase Reverse Immobilization) paramagnetic bead-based chemistry provides an easy, rapid, high yielding, robust and automation-friendly nucleic acid purification procedure that does not require vortexing, centrifugation or filtration steps. The data shows that cfDNA was successfully extracted and detected from human plasma samples using qPCR assays. Both cfDNA and miRNA can be extracted from the same protocol.