Liquid biopsy as the universal DNA-based method for early cancer detection: problems, approaches, solutions

Abstract

Until recently, the establishment of a universal test, allowing the early cancer detection by the analysis of blood, urine or other biological fluids seemed as realistic as the development of "Perpetuum mobile". There are numerous obstacles on this road: above all being the ultra-low concentrations of biomarkers shed by such tumors in the bloodstream. Meanwhile, in attempts to create such a test, the methodology of ultrasensitive DNA analysis has emerged, and stunning practical successes have been achieved in this field over the past few years. The performance of the CancerSEEK test has already reached the threshold for clinical utility of its practical implementation. Techniques based on the analysis of methylation patterns (Galleri test, cfMeDIP-seq) are also rapidly developing. A number of promising studies are based on quite unconventional approaches, for example, the analysis of tumor-associated viral or microbial DNA sequences circulating in plasma. In addition to universal tests aiming at the detection of any or many types of neoplasms in older people, the methods for early DNA-based detection of certain cancer types in selected high-risk groups are being developed. These advances finally make the prospects for introducing liquid biopsy into routine cancer screening look like a matter of the near future.