MYC::IGH rearrangements arise by distinct mechanisms across lymphoma entities. (A-C) Diagrams showing the architecture of MYC::IGH rearrangements at high resolution (top row) and the frequency of each rearrangement partner (bottom row) across BL (A), DLBCL (B), and HGBCL-DH-BCL2 (C). In each circular plot, the outermost ring gives the chromosome ideogram, followed by a genomic coordinate scale, a gene coordinate track including Eμ and 3' regulatory region enhancers in red, and a rainfall plot of intermutation distance with points colored according to whether the mutation overlaps the canonical AID WRCY motif (red) or not (black), including mutations from tumors without rearrangements. Innermost lines show the linkages between MYC and IGH. (D) The frequency of MYC::IGH rearrangements attributable to either CSR or SHM. The frequency of each type of event was compared by FDR-corrected pairwise Fisher exact tests. (E) Expression of MYC determined from RNAseq data, stratified by the region of IGH to which MYC is rearranged. FDR-corrected Wilcoxon tests were used to compare expression levels of each group with DLBCL without MYC-R (“MYC-R Neg”). No RNAseq data were available for any of the HGBCL-DH-BCL2 tumors with MYC-R involving variable or Eμ/IGHM regions. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001. REF, reference group.