Liquid biopsy and tumor heterogeneity in metastatic solid tumors: the potentiality of blood samples

Abstract

In a large number of cancer types, treatment selection depends on the presence of specific tumor biomarkers. Due to the dynamic nature of cancer, very often these predictive biomarkers are not uniformly present in all cancer cells. Tumor heterogeneity represents indeed one of the main causes of therapeutic failure, and its decoding remains a major ongoing challenge in the field. Liquid biopsy is the sampling and analysis of non-solid biological tissue often through rapid and non-invasive methods, which allows the assessment in real-time of the evolving landscape of cancer. Samples can be obtained from blood and most other bodily fluids. A blood-based liquid biopsy can capture circulating tumor cells and leukocytes, as well as circulating tumor-derived nucleic acids. In this review, we discuss the current and possibly future applications of blood-based liquid biopsy in oncology, its advantages and its limitations in clinical practice. We specifically focused on its role as a tool to capture tumor heterogeneity in metastatic cancer patients.

Impact of age‐related T‐cell dynamics on the identification of biomarkers predictive of immunotherapy discontinuation: A prospective cohort study

“…However, the number of studies reporting PBTL biomarkers predictive of ICI efficacy is limited. 21 We hypothesized that this relative lack of success might be attributed to normal, age-related changes in PBTL gene expression that could obscure the identification of effective biomarkers. Peripheral blood was drawn via standard venipuncture no more than 2 weeks before the initiation of ICI therapy.…”

The Effect of Methylselenocysteine and Sodium Selenite Treatment on microRNA Expression in Liver Cancer Cell Lines

“…Recently the potential of miRNAs in diagnostics and cancer research has been recognized. MiRNAs can be detected in serum and may thus be a tool to follow disease progression and relapse [23,24]. Furthermore, the regulatory properties of certain miRNAs may be used as drug targets or mediate drug effects.…”

“…Generally, miRNAs are non-coding, small fragments of RNA, being remarkably stable compared to mRNA. Several studies suggest that circulating miRNA in serum could be a valuable tool for diagnostics and surveillance of disease progression of cancer and other diseases [23,24]. For this reason, it is important to explore how different treatments affect the levels of miRNAs.…”

New Insights into Diffuse Large B-Cell Lymphoma Pathobiology

“…In tumor patients, based on evidence from other solid [ 41 , 42 , 43 ] and hematological malignancies [ 44 , 45 , 46 , 47 ], cell-free DNA (cfDNA) and extracellular vesicles are released by tumor apoptotic cells; DLBCL makes no exception [ 48 , 49 ]. Circulating tumor DNA (ctDNA) is distinguished from other cfDNA by the presence of somatic mutations representative of tumor biology absent in normal cells [ 50 ].…”