There are a large number of biomarkers with potential utility for early cancer detection from blood samples
Few biomarkers have been studied sufficiently with clinical validation to allow their use in combination for screening in the general population.
We used an iterative mapping review of 20,000 references, retrieving 3,990 relevant papers, and identified 788 markers in blood of potential use
Screening for cancer can save lives, but it is difficult to justify individual screening programmes for many cancer types. However, cancers of different types share many attributes, and markers of cancer biology found in the blood. We surveyed the literature to identify known biomarkers using a new mapping approach. With nearly 20,000 papers on the subject, we retrieved 3990 papers, and identified 788 markers in blood of potential use. Most have not been studied enough to justify their use in clinical practice. This evidence based approach should help us to develop a blood-based cancer screening test in the general population.
The Early Cancer Detection Consortium is developing a blood-test to screen the general population for early identification of cancer, and has therefore conducted a systematic mapping review to identify blood-based biomarkers that could be used for early identification of cancer.
A mapping review with a systematic approach was performed to identify biomarkers and establish their state of development. Comprehensive searches of electronic databases Medline, Embase, CINAHL, the Cochrane library and Biosis were conducted in May 2014 to obtain relevant literature on blood-based biomarkers for cancer detection in humans. Screening of retrieved titles and abstracts was performed using an iterative sifting process known as “data mining”. All blood based biomarkers, their relevant properties and characteristics, and their corresponding references were entered into an inclusive database for further scrutiny by the Consortium, and subsequent selection of biomarkers for rapid review. This systematic review is registered with PROSPERO (no. CRD42014010827).
The searches retrieved 19,724 records after duplicate removal. The data mining approach retrieved 3990 records (i.e. 20% of the original 19,724), which were considered for inclusion. A list of 814 potential blood-based biomarkers was generated from included studies. Clinical experts scrutinised the list to identify miss-classified and duplicate markers, also volunteering the names of biomarkers that may have been missed: no new markers were identified as a result. This resulted in a final list of 788 biomarkers.
This study is the first to systematically and comprehensively map blood biomarkers for early detection of cancer. Use of this rapid systematic mapping approach found a broad range of relevant biomarkers allowing an evidence-based approach to identification of promising biomarkers for development of a blood-based cancer screening test in the general population.