Table 2.
Methylation of circulating L1 in blood samples of cancer patients.
| Tumor Location | Clinical Samples | Method | Results | Ref. |
|---|---|---|---|---|
| Colorectal (patients before treatment) |
Plasma | AQAMA qPCR | Significant decrease of L1 MI in cancer patients compared with healthy subjects Association of L1MI with disease progression (advanced stage and distant metastasis) |
[112] |
| Lung (patients before treatment) |
Cell surface-bound fraction of blood | MIRA | Significant decrease of L1 MI in cancer patients compared with healthy subjects Hypomethylation of L1 promoters in cancer patients is more pronounced for the L1 human-specific (L1Hs) family |
[115] |
| Lung (patients before treatment and after antitumor therapy) |
Cell surface-bound fraction of blood | qMSP PCR | Association of L1 MI with tumor histological type Dynamic changes in L1 MI of csb-cirDNA during the follow-up period |
[117] |
| Lung (patients before treatment) |
Cell surface-bound fraction of blood, plasma | qMSP PCR | Significant decrease of L1 MI in csb-cirDNA in cancer patients compared with healthy subjects | [116] |
| Lung (patients before treatment) |
Cell surface-bound fraction of blood, plasma | qMSP PCR | Decrease of L1 MI in cancer patients compared with the joint control group (healthy subjects + patients with bronchitis + COPD patients) and with COPD patients | [118] |
| Diffuse large B cell lymphoma (patients before treatment) |
Plasma | Pyrosequencing | Association of L1 hypomethylation with poor overall survival | [119] |
| Melanoma (patients before treatment) |
Serum | AQAMA qPCR | Decrease of L1 methylation during disease progression (advanced stage) | [120] |
Abbreviations: MIRA, methylated CpG island recovery assay; AQAMA, absolute quantitative assessment of methylated alleles; qMSP-PCR, quantitative methyl-specific PCR; L1 MI, L1 methylation index; csb-cirDNA, cell surface-bound circulating DNA.