Table 1. Baseline characteristics of subjects according to the distribution of DNA methylation in subtypes of tissues.
| Variables | Total | Methylation status | |||||||
|---|---|---|---|---|---|---|---|---|---|
| p16 | MLH1 | MGMT | ≥ 1 of genes | ||||||
| Normal | Tumor | Normal | Tumor | Normal | Tumor | Normal | Tumor | ||
| Sex, n (%) | |||||||||
| Male | 109 (50.5) | 27 (25.7) | 66 (60.6) | 19 (17.4) | 24 (22.0) | 18 (16.5) | 63 (57.8) | 45 (41.3) | 87 (79.8) |
| Female | 106 (49.5) | 35 (33.0) | 52 (49.1) | 19 (17.9) | 25 (23.6) | 13 (12.3) | 56 (52.8) | 51 (48.1) | 80 (75.5) |
| P value a | 0.294 | 0.101 | 0.924 | 0.871 | 0.439 | 0.495 | 0.339 | 0.513 | |
| Age at surgery | |||||||||
| Mean (SD) | 64.3 (14.5) | 62.7 (14.3) | 63.2 (15.7) | 66.2 (12.3) | 67.4 (12.9) | 61.5 (15.2) | 63.9 (14.3) | 63.3 (14.6) | 64.0 (15.0) |
| ≤ 65, n (%) | 107 (49.8) | 32 (29.9) | 63 (58.9) | 18 (16.8) | 21 (19.6) | 19 (17.8) | 62 (57.9) | 51 (47.7) | 87 (81.3) |
| > 65, n (%) | 108 (50.2) | 31 (28.7) | 55 (50.9) | 20 (18.5) | 28 (25.9) | 12 (11.1) | 57 (52.8) | 45 (41.7) | 80 (74.1) |
| P value a | 0.882 | 0.274 | 0.858 | 0.330 | 0.179 | 0.494 | 0.412 | 0.252 | |
| Stage, n (%) | |||||||||
| I | 29 (13.6) | 10 (34.5) | 12 (41.4) | 3 (10.3) | 6 (20.7) | 2 (6.9) | 12 (41.4) | 12 (41.4) | 19 (65.5) |
| II | 78 (36.4) | 23 (30.4) | 45 (57.0) | 13 (16.5) | 16 (20.3) | 9 (11.4) | 44 (55.7) | 35 (44.3) | 63 (79.7) |
| III | 71 (33.2) | 20 (28.2) | 39 (54.9) | 17 (23.9) | 18 (25.4) | 11 (15.5) | 44 (62.0) | 33 (46.5) | 58 (81.7) |
| IV | 36 (16.8) | 9 (25.0) | 22 (61.1) | 5 (13.9) | 9 (25.0) | 9 (25.0) | 19 (52.8) | 16 (44.4) | 27 (75.0) |
| P value a | 0.853 | 0.417 | 0.331 | 0.867 | 0.154 | 0.302 | 0.973 | 0.324 | |
| Recurrence, n (%) | |||||||||
| Absence | 130 (60.7) | 32 (24.6) | 64 (49.2) | 19 (14.6) | 27 (20.8) | 13 (10.0) | 68 (52.3) | 49 (37.7) | 95 (73.1) |
| Presence | 84 (39.3) | 30 (36.5) | 54 (63.5) | 19 (22.4) | 22 (25.9) | 18 (21.2) | 51 (60.0) | 47 (55.3) | 72 (84.7) |
| P value a | 0.068 | 0.027 | 0.200 | 0.409 | 0.029 | 0.326 | 0.012 | 0.065 | |
| Mortality, n (%) | |||||||||
| Absence | 172 (79.9) | 50 (29.1) | 97 (56.4) | 32 (18.6) | 41 (23.8) | 24 (14.0) | 98 (57.0) | 79 (45.9) | 137 (79.7) |
| Presence | 43 (20.1) | 13 (30.2) | 21 (48.8) | 6 (14.0) | 8 (18.6) | 7 (16.3) | 21 (48.8) | 17 (39.5) | 30 (69.8) |
| P value a | 0.854 | 0.236 | 0.655 | 0.546 | 0.808 | 0.392 | 0.496 | 0.218 | |
a P value for between group comparison with regard to methylation status in normal and tumor tissues.