“…Previously, studies had proven implementation of biomarkers from blood as a non-invasive method for CRC screening, particularly during its early stages (stage I or premalignant stage) [ 63 , 64 , 65 , 66 , 67 ]. Examples of the markers evaluated were (1) proteins (hemoglobin) [ 68 , 69 , 70 , 71 ]; (2) deoxyribonucleic acid/DNA from intact cells or blood circulation (including methylation markers) [ 72 , 73 , 74 , 75 , 76 , 77 ]; (3) ribonucleic acid/RNA (messenger RNA, non-coding RNA and microRNA) [ 78 , 79 , 80 , 81 ]; (4) genes (mutation) [ 82 , 83 ]; and (5) low molecular weight metabolites (volatile organic compounds) [ 84 ]. Since the approval of first liquid biopsy-based test by the Food and Drug Administration (FDA) in 2016, numerous blood-based detection methods have been the focus of CRC screening to overcome the above-mentioned difficulties in traditional tissue biopsy testing [ 85 , 86 , 87 ].…”