Globally, more than 19 million people were diagnosed with cancer in 2020. Tremendous progress has been made toward cancer treatment; however, its early detection research has made comparatively limited progress. Despite significant advances, tumor biopsy remains the primary method of a cancer diagnosis. However, there are several limitations to using invasive tumor biopsy for the early detection of solid tumors. These include difficulties in the accessibility of certain tumors, intra-tumor heterogeneity, and changes in tumor genetic composition arising from malignant neoplasms. Furthermore, tissue-based tumor profiles are also subjected to sampling bias, provide only a snapshot of tumor heterogeneity, and repeated sampling is difficult. Towards this, genomic profiles of circulating cell-free tumor DNA (ctDNA) closely match with the corresponding tumors.
Multiple sampling of blood and other biological fluids from a patient is termed “liquid biopsy,” which has important implications for both molecular pathology and clinical oncology. A liquid biopsy allows tumor-derived circulating cell-free DNA, mRNA, non-coding RNAs, and other metabolites to be monitored and analyzed before, during, and after the treatment. Liquid biopsy can be employed to assess tumor burden, residual disease, resistance, and early relapse during treatment. Owing to the minimally invasive nature of liquid biopsy, it offers the potential for easily repeated sampling over time.
Importantly, ctDNA analysis can also be used to identify acquired mutations responsible for drug resistance in certain cancers. ctDNA-based two different liquid biopsy companion diagnostic tests for EGFR mutations are already in clinical practice. In addition, accumulating evidence reveals that non-coding RNAs play a critical role in the pathogenesis of various cancers. The expression levels of non-coding RNAs, particularly long non-coding RNAs and microRNAs, are frequently dysregulated in multiple cancers. Indeed, circulating miRNAs have become one of the most well-studied molecules for the development of liquid biopsy biomarkers for cancer patients.
Globally, more than 19 million people were diagnosed with cancer in 2020. Tremendous progress has been made toward cancer treatment; however, its early detection research has made comparatively limited progress. Despite significant advances, tumor biopsy remains the primary method of a cancer diagnosis. However, there are several limitations to using invasive tumor biopsy for the early detection of solid tumors. These include difficulties in the accessibility of certain tumors, intra-tumor heterogeneity, and changes in tumor genetic composition arising from malignant neoplasms. Furthermore, tissue-based tumor profiles are also subjected to sampling bias, provide only a snapshot of tumor heterogeneity, and repeated sampling is difficult. Towards this, genomic profiles of circulating cell-free tumor DNA (ctDNA) closely match with the corresponding tumors.
Multiple sampling of blood and other biological fluids from a patient is termed “liquid biopsy,” which has important implications for both molecular pathology and clinical oncology. A liquid biopsy allows tumor-derived circulating cell-free DNA, mRNA, non-coding RNAs, and other metabolites to be monitored and analyzed before, during, and after the treatment. Liquid biopsy can be employed to assess tumor burden, residual disease, resistance, and early relapse during treatment. Owing to the minimally invasive nature of liquid biopsy, it offers the potential for easily repeated sampling over time.
Importantly, ctDNA analysis can also be used to identify acquired mutations responsible for drug resistance in certain cancers. ctDNA-based two different liquid biopsy companion diagnostic tests for EGFR mutations are already in clinical practice. In addition, accumulating evidence reveals that non-coding RNAs play a critical role in the pathogenesis of various cancers. The expression levels of non-coding RNAs, particularly long non-coding RNAs and microRNAs, are frequently dysregulated in multiple cancers. Indeed, circulating miRNAs have become one of the most well-studied molecules for the development of liquid biopsy biomarkers for cancer patients.
