cfDNA has been the talk of the town – now more than ever. The number of publications published on cfDNA per year has increased over 15-fold in the last decade (PubMed).
cfDNA, the extracellular DNA that circulates freely in the blood and other bodily fluids, is released from sources such as apoptotic cells in healthy conditions1, necrotic cells in cancer,1 or from fetal cells in maternal blood.2 cfDNA fragments are about 170 bps in length and have a short half-life of about 15 minutes to a few hours.3 Its discovery and utility for various research and clinical applications has revolutionized the field of genomics. Several characteristics of cfDNA, such as concentration, stability and integrity, are significantly different in cancer cells compared to normal cells.4 Studies have also shown that a fraction of cfDNA, called circulating tumor DNA (ctDNA), can be used to determine somatic mutations, copy number variations (CNV) and epigenetic alterations that are characteristic of cancer cells.5,6,7 Analysis of cfDNA in maternal blood can also provide information about chromosomal aneuploidies such as trisomy 13, trisomy 8 and trisomy 21 in the fetus.8 Therefore, the ability to accurately measure and quantify cfDNA as a biomarker has enormous potential for the detection and real-time monitoring of cancer (liquid biopsy) and in prenatal screening (non-invasive prenatal testing, NIPT).
However, despite showing great promise as a tool for precision medicine, the use of cfDNA has not realized its peak yet. Two reasons can account for this:
Given how expensive and time consuming downstream analytical techniques are and how precious the sample is, it is extremely critical to optimize preanalytical factors that may affect cfDNA quality to ensure the results obtained are reliable. In Part 2 of this series, we will discuss these preanalytical factors in detail and provide some tips on how to avoid them.
Roche offers cell-free DNA collection tubes for the collection, stabilization and transportation of whole blood specimens, cfDNA-based non-invasive prenatal test to screen for possible chromosomal conditions in a pregnancy, and ctDNA analysis kits for liquid biopsy assays for oncology research. Check them out.