ABC and GCB subgroups of DLBCLs have distinct methylation signatures. (A) Sixty-nine cases of DLBCLs were studied with the use of HG_17 human promoter array from Roche NimbleGen. The heatmap shows methylation values of 311 probe sets in 69 cases. With the use of the leave one out cross validation method we demonstrated that the 311 probe signature is able to correctly assign ABC and GCB labels to the DLBCL cases with the use of Bayesian predictor with probability cutoff of 0.8 (plot above the heatmap) and predictive accuracy of 91%. (B) Kaplan-Meier estimates of PFS in ABC and GCB subgroups, classified on the basis of 311 methylation signature, show that patients with GCB DLBCL had a higher probability of PFS than patients with ABC DLBCL.