Assessment of Circulating Nucleic Acids in Cancer: From Current Status to Future Perspectives and Potential Clinical Applications

Abstract

Current approaches for cancer detection and characterization are based on radiological procedures coupled with tissue biopsies, despite relevant limitations in terms of overall accuracy and feasibility, including relevant patients’ discomfort. Liquid biopsies enable the minimally invasive collection and analysis of circulating biomarkers released from cancer cells and stroma, representing therefore a promising candidate for the substitution or integration in the current standard of care. Despite the potential, the current clinical applications of liquid biopsies are limited to a few specific purposes. The lack of standardized procedures for the pre-analytical management of body fluids samples and the detection of circulating biomarkers is one of the main factors impacting the effective advancement in the applicability of liquid biopsies to clinical practice. The aim of this work, besides depicting current methods for samples collection, storage, quality check and biomarker extraction, is to review the current techniques aimed at analyzing one of the main circulating biomarkers assessed through liquid biopsy, namely cell-free nucleic acids, with particular regard to circulating tumor DNA (ctDNA). ctDNA current and potential applications are reviewed as well.

Serum albumin and nucleic acids biodistribution: From molecular aspects to biotechnological applications

“…CfNAs are present at low concentrations in the bloodstream of healthy subjects. 28 However, their levels dramatically increase or are deregulated in patients affected by acquired pathologies, including infectious diseases, cancer, and inherited human disorders involving HSA coding gene (e.g., analbuminemia, familial dysalbuminemic hyperthyroxinemia, and familial dysalbuminemic hypertriiodothyroninemia). All these pathological conditions share lower levels of HSA compared to healthy individuals.…”

Role of Cell-Free DNA and Deoxyribonucleases in Tumor Progression

“…Fragments of the mutant KRAS gene, which is a key participant in the intracellular cascades responsible for cell oncotransformation, and the TP53 gene, which plays a key role in triggering apoptosis, are the most frequent in the pool of cfDNA in patients with cancer. Mutant sequences of the EGFR, BRAF, HER2, ALK and BRCA genes, among others, are often found in the blood of patients with various types of cancer [46]. For some genes, an increase in the number of copies has been found both in tumor cells and in the cfDNA pool.…”

Current Technologies for RNA-Directed Liquid Diagnostics

“…A brief summary of all the detection and quantification methods described below is presented in Table 4. • Ultrasensitive • 0.01% limit detection [115,116] • Divide in so a way that each particle is attached to a magnetic bead like a microreactor • Low sensitivity due to missing target amplification [119] 3.5.1. Direct Detection and Quantification of RNA Quantification of miRNA after the initial isolation is a crucial step for all further downstream applications.…”