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Table 2 MGMT methylation frequencies and methylation level in methylated glioma samples

From: MGMT promoter methylation in gliomas-assessment by pyrosequencing and quantitative methylation-specific PCR

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)
  1. Abbreviations: PMR, Percentage of methylated reference, qMSP, quantitative methylation specific PCR, IQR, interquartile range
  2. a)Primary glioblastoma patients treated with standard radiation and at least concomitant temozolomide