Single genes of 16-gene methylation signature can differentiate between ABC and GCB subtypes of primary DLBCLs across platforms. (A) Heatmaps represent EpiTYPER results for 3 of the 16 genes: IKZF1, GALNS, and PMM2 (for the rest of the 16 genes, see supplemental Figure 4), performed in 5 randomly selected ABC and 5 GCB primary DLBCL cases. Rows of the heatmap represent individual CpGs in the promoter regions with color reflecting methylation value; whereas columns represent individual cases with class label on the bottom. A t test with methylation values from all tested CpGs was performed between ABC and GCB subtypes, with P value represented below each heatmap. Panels in the middle show the methylation levels for each CpG averaged in ABC and GCB cases. Panels on the right show the average methylation level of all CpGs in ABC and GCB cases with error bar for standard deviation. (B) Q-PCR was performed in 5 ABC and 5 GCB DLBCLs with primers specific for IKZF1, GALNS, and PMM2. The amount of transcript was calculated by normalizing to internal control gene RPIL3 and is shown as an average within the subtype. It shows the trend for greater expression in ABC than GCB DLBCLs, which is inversely correlated with greater DNA methylation of the corresponding promoters.