Use of blood-based biomarkers for early diagnosis and surveillance of colorectal cancer

Abstract

Early screening for colorectal cancer (CRC) holds the key to combat and control the increasing global burden of CRC morbidity and mortality. However, the current available screening modalities are severely inadequate because of their high cost and cumbersome preparatory procedures that ultimately lead to a low participation rate. People simply do not like to have colonoscopies. It would be ideal, therefore, to develop an alternative modality based on blood biomarkers as the first line screening test. This will allow for the differentiation of the general population from high risk individuals. Colonoscopy would then become the secondary test, to further screen the high risk segment of the population. This will encourage participation and therefore help to reach the goal of early detection and thereby reduce the anticipated increasing global CRC incidence rate. A blood-based screening test is an appealing alternative as it is non-invasive and poses minimal risk to patients. It is easy to perform, can be repeated at shorter intervals, and therefore would likely lead to a much higher participation rate. This review surveys various blood-based test strategies currently under investigation, discusses the potency of what is available, and assesses how new technology may contribute to future test design.

Keywords: Colorectal neoplasms, Early detection of cancer, Colonoscopy, Biological markers, Blood, Messenger RNA, MicroRNA, Long non-coding RNA, DNA methylation, Microsatellite instability, Loss of heterozygosity, High-throughput nucleotide sequencing, Mass spectrometry, Real-time polymerase chain reaction, Microarray analysis

Core tip: Current colorectal cancer screening modalities are severely inadequate for global application because of high costs and a low participation rate. The alternative is to develop a blood-based screening test based on biomarkers which can replace colonoscopy as a first-line screening tool. The blood-based test should identify the high risk population, which will then be followed by colonoscopy as a secondary test. This review surveys the various experimental approaches and latest research into ideal biomarkers for the initial screening test, the pros and cons of each method and their potential to lead to a future screening test.