Fig. 4

Methylation analysis of the promoter region in the MGMT and SFRP2 gene. a Schematic depiction of two regions (Mp and Eh region) of the MGMT promoter for methylation, and results of a panel of representative fluorescent bisulphite PCR following restriction enzyme analysis. Methylated samples had the new fragment cleaved by the restriction enzyme (black triangles). White triangles represent unmethylated alleles. M and U denote methylated and unmethylated, respectively. A grey bar denotes an untranslated exon. b The frequencies of MGMT promoter methylation status among the POLE, MSI-M, MSI-U, and non-MSI groups. Extensive methylation is defined as 5.0% or more methylation on both Mp and Eh regions. Partial methylation is defined as 5.0% or more methylation on either Eh or Mp region. c Schematic depiction of two regions (R1 and R2 region) of the SFRP2 promoter for methylation, and results of a panel of representative fluorescent bisulphite PCR following restriction enzyme analysis. Methylated samples had the new fragment cleaved by the restriction enzyme (black triangles). White triangles represent unmethylated alleles. M and U denote methylated and unmethylated, respectively. A black bar denotes translated exon. d The frequencies of SFRP2 promoter methylation status among the POLE, MSI-M, MSI-U, and non-MSI groups. Extensive methylation is defined as 5.0% or more methylation on both R1 and R2 region. Partial methylation is defined as 5.0% or more methylation on either R1 or R2 region. The number in each column denotes the number of samples classified in each category divided by MGMT or SFRP2 methylation status