[The importance of "free" nucleic acids in the non-invasive diagnostics]

There is a great interest to determine the physiological role of "free" nucleic acids, and to use them in the clinical diagnostics. These could be DNA, mRNA, microRNA and long non-coding RNA molecules, they are in the body fluids, like serum, tear, saliva, etc. Their exact role in the normal and pathological physiological processes is still in the focus of the research, while their use in the diagnostics is becoming more and more important. The use of "free" DNA in the non-invasive prenatal diagnosis is the first clinical application of the new generation sequencers, these methods are able to reach 99.9% specificity and sensitivity for the detection of the most common trisomies. There are promising results in their use in the diagnosis and classification of heart and cardiovascular diseases. In oncology the possibility to use the "liquid biopsy" captured the attention of not only researchers and clinicians, but the whole community. There is not enough data until today for the clinical utility and applicability of these methods. Orv. Hetil., 2016, 157(48), 1900-1909.