Data-based precision medicine could be possible if we could accurately analyze molecular information from cancer tissues. The reason for the rapid rise of liquid biopsy in cancer diagnosis is that it is non-invasive and economical compared to tissue biopsy. More importantly, it could repetitively do the tests and possibly to analyze complete cancer information. In particular, circulating tumor DNA (ctDNA)-based liquid biopsy is taking the spotlight in the liquid biopsy market, as ctDNA is considered more efficient than other biomarkers such as circulating tumor cells (CTCs) or extracellular vesicles (EVs).
While liquid biopsy is rapidly emerging as an alternative to tissue biopsy, it is not yet the gold standard for cancer diagnosis. This is due to the technology limitations of liquid biopsy that prevent precise analysis of trace amount of biomarkers from body fluids. If the technology that can accurately detect ctDNA in the blood is available, ctDNA liquid biopsy will be applicable to the entire process of cancer diagnosis and eventually could even replace tissue biopsy.
(A) Box and whisker plot of patients’ ctDNA concentration compared with cancer stages. The ctDNA concentration in patients with Stage I cancer was significantly lower than that in patients with Stage IV cancer (P = 0.0149). (B) Box and whisker plots of each patient’s LTM (cm) compared with cancer size. (C) Colored ovals represent the range of ctDNA concentration compared with LTM for each patient based on cancer stage.
Source: Ying-Chi Yang et al, Circulating tumor DNA detectable in early- and late-stage colorectal cancer patients, bioscience Reports, 2018. July, p.5 ctDNA could be used from diagnosis in the early stages of cancer development to monitoring in later stages, as it appears from the very beginning of cancer development
According to the report, the detection sensitivity of 0.01% to 1% is required to analyze ctDNA from the early-stage patients, but current liquid biopsy technologies fail to attain a detection sensitivity of 0.01%. Although ctDNA is an efficient specimen throughout the entire cycle of cancer, the technology’s limitations make clinical use difficult. Some of the latest technologies, such as ddPCR, claims that it reached 0.01%, but the reality is that the testing methods are very complex and cannot be applicable on a large scale due to economic constraints. Therefore, liquid biopsy could replace tissue biopsy only when it realizes 0.01% of detection sensitivity.
As detection sensitivity is a limiting factor in enabling the widespread use of a liquid biopsy, many companies, are competing to improve detection sensitivity. Currently, the practical detection sensitivity of ctDNA that does not sacrifice diagnostic quality remains at around 0.1 to 1%. It is mainly because false positives still arise during gene amplification, even when lowering the ctDNA sensitivity threshold.
GENECAST has figured out a way to overcome this barrier using ADPS™, which can analyze ctDNA with a sensitivity threshold as low as 0.01%, free of false positives.
ADPS™, developed by GENECAST using a combination of proprietary technologies, has achieved the detection sensitivity of 0.01% necessary for accurate cancer diagnosis using ctDNA.
ADPS™ is a qPCR-based technology that is faster and easier to use than other testing methods.
For more information about ADPS™, click “What is ADPS™?” Or "How does ADPS™ achieve ultra-high detection sensitivity?"