Table 3.
Characteristic collected from included studies
| Studies | Method | Studied groups | Methylation status | Potential Clinical Value | ||
|---|---|---|---|---|---|---|
| NT | BTLs | DTCs | ||||
| Venkataraman et al. (1999) | MSP | NT (5), PTC (16), FTC (2) | 2/5 | – | 8/18 | Chemical demethylation therapy |
| Neuman et al. (2004) | MSP | ST (14), CTN (14) | 0/14 | – | 6/14 | Could be a regulatory mechanism of NIS transcription |
| Smith et al. (2007) | MSP | Controls (FA (10), goiters (15), normal thyroids (2)), PTC (32) | 0 | 0 | 7/32 | Marker of virulence |
| Stephen et al. (2011) | MSP | NT (5), hyperthyroid (3), PTC (11), FTC (2) | 1/5 | 1/3 | 7/13 | Early event |
| Galrão et al. (2013) | SQ-MSP | BTLs (10), PTC (18), FTC (2) | – | 2.23 | 1.92 | Very frequent event |
| Galrão et al. (2014) | BSP | BTLs (10), PTC (18), FTC (2) | – | 23.2% | 66.1% | Early event |
| Choi et al. (2014) | BSP and MSP | NT (24), PTC (24) | 29% | – | 58% | Related to BRAF (V600E) mutation |
| Stephen et al. (2015) | QMSP | ANT (24), FTC-Hurthle (26), FTC-Classic (27) | > 0.0 | – | > 0.0 | Early changes in thyroid tumorigenesis regardless of cell type |
| Stephen et al. (2018) | QMSP | NT (71), FA (83), PTC (85), FTC (90) | 0.001(0.002) |
0.014 (0.041) |
PTC (0.009(0.027)) FTC (0.02(0.07)) |
– |
Methylation status of NIS gene promoter: MSP, SQ-MSP, BSP, and QMSP results were expressed as methylated/total samples, arbitrary unit (AU), percentage, and mean (SD), respectively
MSP methylation-specific PCR, SQ-MSP semi-quantitative MSP, QMSP quantitative MSP, BSP Bisulfite-sequencing PCR, ST surrounding tissue, CTN cold thyroid nodules, NT normal thyroid, FA follicular adenoma, BTLs benign thyroid lesions, TC thyroid cancer, FTC follicular thyroid cancer, PTC papillary thyroid cancer, DTC differentiated thyroid cancer, ANT adjacent normal tissue