Table 2 MGMT methylation frequencies and methylation level in methylated glioma samples
Group | qMSP results | Pyrosequencing results | |||
|---|---|---|---|---|---|
Median and IQR | Median and IQR | ||||
calculated from PMR | calculated from | ||||
Methylated samples | MGMT assay | MGMT_1 assay | Methylated samples | mean CpG methylation | |
Low-grade gliomas | 9/35 (25.7%) | 3.30 (0.78-19.66) | 0.50 (0.29-2.57) | 34/35 (97.1%) | 16.98 (10.97-38.29) |
Astrocytoma WHO grade II | 2/10 (20.0%) | 1.19 (0.85-1.54) | 0.30 (0.29-0.30) | 10/10 (100.0%) | 12.56 (7.24-16.68) |
Oligodendroglioma WHO grade II | 1/6 (16.7%) | 0.78 - | 0.87 - | 5/6 (83.3%) | 29.51 (24.23-33.17) |
Oligoastrocytoma WHO grade II | 6/17 (35.3%) | 11.72 (3.42-24.16) | 1.54 (0.32-7.83) | 17/17 (100.0%) | 24.90 (14.41-47.52) |
Low-grade neuroepithelial tumours (not otherwise specified) | 0/2 (0.0%) | - | - | 2/2 (100.0%) | 6.83 (5.33-8.32) |
High-grade gliomas | 37/99 (37.4%) | 9.18 (4.39-17.81) | 5.59 (1.89-12.37) | 54/99 (54.5%) | 47.14 (18.50-62.87) |
Anaplastic astrocytoma WHO grade III | 1/4 (25.0%) | 24.19 - | 22.35 - | 2/4 (50.0%) | 55.82 (52.95-58.70) |
Anaplastic oligodendroglioma WHO grade III | 6/6 (100.0%) | 19.30 (7.71-54.53) | 11.61 (6.68-16.09) | 6/6 (100.0%) | 70.85 (52.98-82.52) |
Anaplastic oligoastrocytoma WHO grade III | 1/3 (33.3%) | 17.81 - | 0.90 - | 2/3 (66.7%) | 52.99 (48.03-57.94) |
Glioblastoma WHO grade IV | 29/86 (33.7%) | 7.98 (4.00-14.55) | 5.39 (1.89-11.37) | 44/86 (51.2%) | 43.31 (12.05-61.04) |
Primary glioblastoma | 27/80 (33.8%) | 8.67 (3.85-15.33) | 5.59 (1.80-11.48) | 40/80 (50.0%) | 40.68 (11.12-59.05) |
Included in survival analysis a | 19/58 (32.8%) | 5.53 (2.58-10.42) | 3.22 (1.14-10.26) | 29/58 (50.0%) | 34.88 (10.64-48.73) |
Secondary glioblastoma | 2/6 (33.3%) | 5.76 (5.18-6.34) | 2.75 (2.41-3.08) | 4/6 (66.7%) | 55.26 (42.67-63.93) |
All glioma samples | 46/134 (34.3%) | 8.33 (3.40-18.55) | 4.36 (0.88-11.54) | 88/134 (65.7%) | 34.03 (12.42-54.83) |