Written by A. Hammouda: Over the last decade, there has been emerging interest in liquid biopsy as a powerful tool in the oncology field. Currently, it is the most innovative methodology in medical oncology. It has a high potential as a tool for screening and early detection. It can also aid in personalizing the cancer therapy and real-time assessment of treatment response.
The elements that compose the liquid biopsy are circulating tumor cells, circulating tumor nucleic acids, free of cells or contained in exosomes, microvesicles, and platelets. Liquid biopsy studies are performed on various biofluids extracted in a non-invasive way: blood, urine, saliva, or cerebrospinal fluid.
Here is a comprehensive review: Liquid Biopsy as Novel Tool in Precision Medicine: Origins, Properties, Identification and Clinical Perspective of Cancer’s Biomarkers.
A list of some commercially available liquid biopsy products
Guardant360 Response™ test offered by Guardant Health: This is the first FDA-approved liquid biopsy test. It analyzes cell-free DNA (cfDNA) from a blood sample to detect genomic alterations in solid tumors. It provides information on mutations, amplifications, and fusions across multiple cancer genes, aiding in treatment selection and monitoring of treatment response.
FoundationOne®Liquid CDx developed by Foundation Medicine: This is an is FDA-approved liquid biopsy test that analyzes circulating tumor DNA (ctDNA) to identify genomic alterations in over 300 cancer-related genes. It is used for guiding treatment decisions in patients with advanced cancer and can also provide insights into potential targeted therapy options and clinical trial eligibility.
OncoBEAM manufactured by Sysmex Inostics: This is a liquid biopsy platform that utilizes digital PCR technology to detect and quantify circulating tumor DNA (ctDNA) in blood samples. It offers assays for various cancer types, including colorectal cancer, lung cancer, breast cancer, and melanoma, enabling non-invasive monitoring of disease progression and treatment response.
Exosomal RNA Isolation Kit developed by Norgen Biotek Corp.: This Kit allows for the isolation and analysis of exosomal RNA from various biofluids, including blood, urine, and saliva. Exosomes carry nucleic acids derived from tumor cells, making them valuable targets for liquid biopsy-based cancer diagnostics and biomarker discovery.
PGDx elio plasma complete assay offered by Personal Genome Diagnostics (PGDx): This is an end-to-end kitted liquid biopsy research solution that analyzes circulating tumor DNA for genetic alterations in cancer. It evaluates a comprehensive panel of 500+ genes including SNVs, indels, bTMB, MSI, LOH, and select amplifications and translocations despite requiring a low DNA input.
PGDx elio plasma focus assay offered by Personal Genome Diagnostics (PGDx): This is a targeted liquid biopsy assay for research. It evaluates a targeted panel of 33 well-characterized cancer genes using circulating tumor DNA.
Signatera™ developed by Natera: This is a highly sensitive and personalized molecular residual disease assay (MRD) using circulating tumor DNA (ctDNA), custom designed for each patient to help identify relapse earlier than standard of care tools.
LIQUIDPlexTM ctDNA 28 Kit (Diagnóstica Longwood): This is an advanced and user-friendly solution for targeted next generation sequencing (NGS) of circulating cell-free tumor DNA (ccfDNA/cfDNA/ctDNA) from 28 genes commonly associated with solid tumor type cancers.
Cobas EGFR Mutation Test v2 (Roche): This is a real-time PCR test that identifies 42 mutations in exons 18, 19, 20 and 21 of the epidermal growth factor receptor (EGFR) gene, including the T790M resistance mutation. It is designed to enable testing of both tissue and plasma specimens with a single kit, and allows labs to run tissue and plasma on the same plate simultaneously.
Galleri® test from Grail: This test is designed to detect early-stage cancers by analyzing cell-free DNA (cfDNA) in the blood. It is the first multi-cancer early detection test that looks for a signal shared by 50+ types of cancer with a single blood test.
myRisk (Myriad Genetics): This test is a powerful tool that evaluates 48 genes to help healthcare providers identify their patients’ risk of developing 11 different types of hereditary cancer. It lays the foundation for personalized care plans that can be used to help patients make confident, informed decisions about their medical management.
CNSide™ assay (Biocept.com): This assay detects and quantifies tumor cells in cerebrospinal fluid in patients with carcinomas or melanomas with suspected CNS metastases.
It is important to note that this is not an exhaustive list. New liquid biopsy products are being developed all the time. Some have already got out of the market and are no longer available. Always keep informed.
Advances of liquid biopsy in early cancer detection
City of Hope and TGen develop fragmentomic sequencing method. Using smaller blood samples, the fragmentomics approach is capable of identifying cancer at an earlier stage. Link
Grail details tumor burden estimation method that could support residual disease and cancer monitoring. The technique, called tumor methylated fraction (TMeF), holds promise for various monitoring use cases, including detection of minute residual disease in patients with early-stage, potentially curable cancers, and monitoring cancer progression or response to treatment in later-stage disease. Link
Novel proteomics-based plasma test for early detection of multiple cancers in the general population. Link
Advances of liquid biopsy in treatment guidance and monitoring
Liquid biopsy predicts radiotherapy benefit in metastatic lung cancer. Measuring circulating tumor DNA (ctDNA) prior to potential consolidative radiation therapy can reveal whether an individual’s cancer has spread to a few tumor sites or spread more widely throughout the body, thus helping physicians determine the appropriate treatment method more effectively. Link
Novigenix utilizes liquid biopsy and AI to predict how patients will respond to cancer immunotherapy, aiding in personalized treatment decisions. Link
Biomarkers of Aggressive Prostate Cancer at Diagnosis. Link
Challenges and discussions
Liquid biopsy represents an exciting frontier in cancer diagnostics—one that holds great promise for improving patient care and outcomes.
Still, liquid biopsies aren’t right for every patient. Certain cancers—such as early-stage cancers, small cell lung cancer and gynecological cancers—don’t shed much DNA and therefore don’t provide useful information. Some patients have unique DNA that can skew test results, making false positives a possibility. Any cancer detected in a liquid biopsy still might need follow-up with a regular biopsy.
Overall, liquid biopsy research continues to make significant strides. Early detection, treatment guidance, and monitoring are all experiencing advancements, but challenges remain. Stay tuned for more exciting developments in this field with the potential to revolutionize cancer care.
See also:
Cancer Blood Tests Revolutionize Oncology
Cancer Blood Test Shows Low Positive Predictive Value
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