Liquid biopsy for the evaluation of molecular alterations in human cancer

Liquid biopsy can detect molecular biomarkers in body fluids. The profile of circulating tumour DNA (ctDNA) allows to identify the risk of recurrence, therapeutic targets and drug resistance. This project was aimed to analyse the mutational status of RAS, BRAF and EGFR genes from blood samples of patients with metastatic colorectal and lung cancer, to characterise cancers through metabolites and extracellular vesicles (EVs) to exploit novel potential biomarkers. For these purposes, blood samples were analysed using the BEAMing technology and qPCR with IdyllaTM Mutation Test. Concordance analyses between tissue sample plasma generally showed high concordance and substantial agreement. Moreover, RAS and EGFR mutational profiles were analysed during therapy and several associations with clinical features emerged. We then investigated the profile of circulating miRNAs in patients with early and established form of Idiopathic Pulmonary Fibrosis (IPF) along with lung cancer patients, through small RNA sequencing and uncovered important differences between the groups and with healthy controls: in particular, 30 differentially expressed miRNAs, 21 up-regulated and 9 down-regulated in IPF compared to healthy subjects; in patients with E-IPF compared to IPF 127 up-regulated and 109 down-regulated differentially expressing miRNAs were identified while 20 ci-miRNA were down-regulated in E-IPF compared to controls and moreover 43 downregulated in LC patients compared to controls. Moreover, a functional analysis using Gene Ontology revealed altered terms related to signalling mechanisms mediated by GTPases, cell adhesion molecules, MAPKs and Ras signalling. Analysis through KEGG ontology showed significant enrichment for the term NSCLC, specifically relevant genes (ALK, EGFR, kinases, etc.). EVs in the plasma of mCRC and mLC patients are significantly more abundant than in controls. Overall, these findings suggest that mutational testing of plasma is a valuable tool for the clinical management of lung cancer and colorectal cancer. Validation in larger cohorts is essential to evaluate concordance rates, establish sensitivity thresholds, and identify correlations with clinical outcomes that will guide best treatment option for patients. In conclusion, our data supports the integration of liquid biopsy in the routine of clinical practice for patients with metastatic colorectal and lung cancers. Early detection of resistance through liquid biopsy may change treatment paradigms, enabling more precise decisions during treatment decisions and improving patient outcomes.