Table 2.
Methylation profile of MGMT and p16 genes in tissue and blood samples of study groups.
| Gene methylation | Groups | Tissue | Blood | ||||
|---|---|---|---|---|---|---|---|
| M* | U | P valuea | M* | U | P valuea | ||
| MGMT | Control (n = 16) | 2 (13%) | 14 (87%) | Ref | 1 (6%) | 15 (94%) | Ref |
| PMOLs (n = 54) | 32 (59%) | 22 (41%) | 0.001 | 21 (39%) | 33 (61%) | 0.0135 | |
| PMOL subtypes | |||||||
| LKP (n = 22) | 16 (73%) | 6 (27%) | 0.0002 | 9 (41%) | 13 (59%) | 0.0166 | |
| LKPD (n = 11) | 8 (73%) | 3 (27%) | 0.0015 | 6 (55%) | 5 (45%) | 0.0049 | |
| SMF (n = 13) | 6 (46%) | 7 (54%) | 0.0437 | 4 (31%) | 9 (69%) | 0.0821 | |
| OLP (n = 8) | 2 (25%) | 6 (75%) | 0.4386 | 2 (25%) | 6 (75%) | 0.1904 | |
| OSCC (n = 76) | 58 (76%) | 18 (24%) | 0.0001 | 43 (57%) | 33 (43%) | 0.0002 | |
|
| |||||||
| P valueb | PMOLs versus OSCC | — | — | 0.0379 | — | — | 0.0468 |
|
| |||||||
| p16 | Control (n = 16) | 2 (13%) | 14 (87%) | Ref | 0 (0%) | 16 (100%) | Ref |
| PMOLs (n = 54) | 31 (57%) | 23 (43%) | 0.0016 | 18 (33%) | 36 (67%) | 0.0074 | |
| PMOL subtypes | |||||||
| LKP (n = 22) | 15 (68%) | 7 (32%) | 0.0007 | 10 (45%) | 12 (55%) | 0.0017 | |
| LKPD (n = 11) | 4 (36%) | 7 (64%) | 0.1428 | 2 (18%) | 9 (82%) | 0.0763 | |
| SMF (n = 13) | 8 (62%) | 5 (38%) | 0.0057 | 6 (46%) | 7 (54%) | 0.0023 | |
| OLP (n = 8) | 4 (50%) | 4 (50%) | 0.0455 | 0 (0%) | 8 (100%) | NA | |
| OSCC (n = 76) | 62 (82%) | 14 (18%) | 0.0001 | 53 (70%) | 23 (30%) | 0.0001 | |
|
| |||||||
| P valueb | PMOLs versus OSCC | — | — | 0.0026 | — | — | 0.0001 |
M: methylated, U: umethylated, and Ref: reference; aChi-square test considering control as reference category; bChi-square test considering PMOLs as reference category.
*Methylated group includes samples showing complete methylation (only methylated amplicon) as well as samples showing partial methylation (both methylated and unmethylated amplicons).