Table 2.
Abnormally methylated genes as potential circDNA blood-based colorectal cancer detection biomarkers
| Potential biomarkers | CRC sensitivity (%) | CRC specificity (%) | Ref. |
| ALX4 | 40-83 | 70-82 | [67,76] |
| TFPI2 | 76-89 | - | [77-80] |
| SDC2 | 92 | - | [81] |
| RUNX3 | 65 | 100 | [82,83] |
| NEUROG1 | 52-64 | 91 | [84] |
| MGMT | 39 | 96 | [74] |
| RARβ2 | 24 | 100 | [74] |
| NGFR | 51 | 84 | [85] |
| 9-Sep | 48-90 | 86-93 | [64-67,70,86] |
| TMEFF2 | 65 | 69 | [85] |
| Vimentin | 59 | 93 | [41] |
| RASSF2A | 58 | 100 | [74] |
| Wif-1 | 74 | 98 | [74] |
| APC | 6 | 100 | [87] |
| hMLH1 | 43 | 98 | [87] |
| HTLF | 21-34 | 98-100 | [87,88] |
| SFRP2 | 67 | 94 | [89] |
| CDKN2A/P16 | 71 | 100 | [83] |
| Panel: SEPT9, HLTF and ALX4 | 74-88 | 90-96 | [68] |
| Panel: SEPT9 and ALX4 | - | - | [67] |
| Panel: MGMT, RASSF2A, Wif-1 gene | 86.5 | - | [74] |
| Panel: BMP3, NDRG4, vimentin, TFPI2, mutant KRAS and β-actin | 87 | - | [69] |
| Panel: AGTR1, WNT2, SLIT2 | 78 | - | [71] |
| Panel: CINP1, FBN1, INA, SNCA, MAL and SPG20 | 90-99 | - | [73] |
| Panel: CYCD2, HIC1, PAX5, RASSF1A, RB1 and SRBC | 84 | 68 | [72] |
| Panel: THBD and C9orf50 | 71 | 80 | [75] |
| RASSF1A, E-cadherin | - | - | [72,90] |
| CAHM | - | - | [91] |
| FRP2, TPEF/HPP1 | - | - | [83,84,92] |
ALX4: Aristaless-like homeobox 4; TFPI2: Tissue factor pathway inhibitor 2; SDC2: Syndecan 2; RUNX3: Runt-related transcription factor 3; NEUROG1: Neurogenin 1; MGMT: O-6-methylguanine-DNAmethyltransferase; RARβ2: Retinoic acid receptor β2; NGFR: Nerve growth factor receptor; SEPT9: Septin 9; TMEFF2: Transmembrane protein with EGF-like, and two follistatin-like domains 2; RASSF2A: Ras association domain family 2 (isoform A); Wif-1: Wnt inhibitory factor-1; APC: Adenomatosis polyposis coli; hMLH1: MutL homolog 1; HTLF: Helicase-like transcription factor; SFRP2: Secreted frizzled-related protein 2; CDKN2A/P16: Cyclin-dependent kinase inhibitor 2A; BMP3: Bone morphogenetic protein; NDRG4: N-myc downstream regulated family member 4; KRAS: Kirsten rat sarcoma 2 viral oncogene homolog; AGTR1: Tissue fac angiotensin II receptor type 1; WNT2: Wingless-type MMTV integration site family member 2; SLIT2: Slit homolog 2 (Drosophila); CINP1 FBN1: Fibrillin 1; SNCA: α-synuclein gene; SPG20: Spastic paraplegia-20; CYCD2: D-type cyclin gene; HIC1: Hypermethylated in cancer 1; RASSF1A: Ras association domain family 1 (isoform A); RB1: Retinoblastoma tumor suppressor; SRBC: Sheep red blood cells; THBD: Thrombomodulin; C9orf50: Chromosome 9 open reading frame 50; FRP2: Frizzled related protein 2; TPEF/HPP1: Transmembrane protein containing epidermal growth factor, follistatin domain/hyperplastic polyposis 1.