Copy Number Alteration and Mutational Profile of High-Grade B-Cell Lymphoma with IMYC/I and IBCL2/I and/or IBCL6/I Rearrangements, Diffuse Large B-Cell Lymphoma with IMYC/I-Rearrangement, and Diffuse Large B-Cell Lymphoma with IMYC/I-Cluster Amplification

Diffuse large B-cell lymphoma (DLBCL) is one of the most frequent non-Hodgkin lymphomas. DLBCL with MYC alteration is classified as (1) high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (double/triple-hit lymphoma; DHL/THL), (2) DLBCL with MYC rearrangement (single-hit lymphoma; SHL), and (3) DLBCL with MYC-cluster amplification (MCAD). This research analyzed these three lymphoma subtypes using an integrative approach, including in situ hybridization (FISH), whole-genome copy number, and targeted next-generation sequencing (NGS). There are differences between them. Diffuse large B-cell lymphoma (DLBCL) with MYC alteration is classified as high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (double/triple-hit lymphoma; DHL/THL), DLBCL with MYC rearrangement (single-hit lymphoma; SHL) and DLBCL with MYC-cluster amplification (MCAD). To elucidate the genetic features of DHL/THL, SHL, and MCAD, 23 lymphoma cases from Tokai University Hospital were analyzed. The series included 10 cases of DHL/THL, 10 cases of SHL and 3 cases of MCAD. The analysis used whole-genome copy number microarray analysis (OncoScan) and a custom-made next-generation sequencing (NGS) panel of 115 genes associated with aggressive B-cell lymphomas. The copy number alteration (CNA) profiles were similar between DHL/THL and SHL. MCAD had fewer CNAs than those of DHL/THL and SHL, except for +8q24. The NGS profile characterized DHL/THL with a higher “mutation burden” than SHL (17 vs. 10, p = 0.010), and the most relevant genes for DHL/THL were BCL2 and SOCS1, and for SHL was DTX1. MCAD was characterized by mutations of DDX3X, TCF3, HLA-A, and TP53, whereas MYC was unmutated. In conclusion, DHL/THL, SHL, and MCAD have different profiles.