Detection and characterization of circulating cell free tumor DNA in cancer patients with malignant solid tumors. Liquid biopsy: a new tool in molecular pathology?

Abstract: The term liquid biopsy comprises methods of blood-based analysis of nucleic acids, which are increasingly under discussion in oncology and personalized medicine, and are already applied in individual cases. The analysis of tumor markers, which in certain tumor diseases can be found as protein markers in vast amounts in the blood, constitutes a primary form of liquid biopsy. Cell-free circulating DNA fragments in the blood (ctDNA), which reflect the genetic profile of a tumor cell and are released in different ways by the tumor, represent a new class of more specific and sensitive biomarkers that can be correlated with the dynamics of the tumor disease. New technologies based on PCR and sequencing techniques pave the way for diagnostic approaches to define molecular tumor characteristics, not only in tumor tissue but also in the blood, by analyzing cell-free circulating DNA. The combination of molecular profiling of the tumor with ctDNA analytics by liquid biopsy is a promising step in the advancement of precision medicine.