Accelerating Early Cancer Detection
Cancer kills 10 million people annually worldwide and 600,000 in the United States alone. Fortunately, we are now able to identify some cancers much earlier than previously possible. This is due to a process called comprehensive genome profiling (CGP), a discovery credited to Meredith Halks-Miller, MD, who was running experiments on expectant mothers and their newborns. She noticed that, in some cases, the blood of the newborn was normal, while that of the mother contained markers that Halks-Miller believed might signal cancer. Her research and that of others found this to be true. This led to the development of a test that can detect some cancers before clinical symptoms appear.
This test can identify more than 50 solid tumors types across all growth stages. Research using this assay resulted in production of the Circulating Cell-Free Genome Atlas (CCGA), which is a list of the tumors the test can identify. In producing this atlas, thousands of participants were recruited — some with newly diagnosed cancers, and some without disease. The goal was to compare tumor DNA profiles and build a genomic picture of early stage cancer.
A recent article in Cancer Science; Tokyo1 discussed this test and the CCGA in detail. This assay uses liquid biopsies, including blood and urine, that make it possible to detect, analyze and monitor cancer cells. Alterations can then be characterized with DNA sequencing. The circulating DNA particles are a result of programmed cell death, microenvironmental stress, and therapeutic effects, all of which induce physiological events that produce DNA fragments.
The use of CGP technology can help identify targetable genomic alterations, which are alterations in the signaling pathways that control cell-cycle progression, apoptosis and cell growth. These are common hallmarks of cancer.2 This test can be used to detect certain types of head and neck squamous cell carcinomas, as well as breast, lung, thyroid, colon, prostate and kidney tumors, among others.
One of the advantages of this technique is that the sample is not subject to the degradation associated with formalin fixation. But the accuracy of plasma samples can be affected by a number of factors, including inflammatory diseases, autoimmune diseases, smoking, pregnancy and exercise. It is important to note that both false positives and false negatives are possible.
This next-generation sequencing provides a better view of tumor heterogeneity, and allows real-time monitoring of a cancer’s evolution. This testing is currently available in a number of countries, including the U.S. The test can detect multiple biomarkers in the early stages of the tumor and thus increases the efficacy and economics of cancer care. With a single assay, therapists can identify the tumor and suggest actionable alterations in treatment. While this test does not cover all tumors and its use is still being expanded, CGP technology represents a powerful new tool in the fight against cancer.
Thomas G. Wilson Jr., DDS
Editor in Chief
- Sunami K, Bando H, Yatabe Y, et al. Appropriate use of cancer comprehensive genome profiling essay using circulating tumor DNA. Cancer Sci. 2021;112:3911–3917.
- Sanchez-Vega F, Mina M, Armenia J, et al. Oncogenic signaling pathways in The Cancer Genome Atlas. Cell. 2018;173:321–337.e10.
From Decisions in Dentistry. January 2022;8(1)4.