The origin, diagnosis, and prognosis of oligomannose-type diffuse large B-cell lymphoma

The acquisition of N-glycosylation sites that are occupied by oligomannose-type glycans in the immunoglobulin complementarity-determining region (CDR) is an early, clonal, tumor-specific identifier of follicular lymphoma (FL). CDR-located N-glycosylation sites are also acquired in germinal center B-cell-like diffuse large B-cell lymphomas (GCB-DLBCLs), but their significance is less defined. We used RNA sequencing immunoglobulin assembly to determine frequency and CDR location of the acquired N-glycosylation sites (AGSs) in 2 independent DLBCL cohorts. Composition of the glycans occupying the AGSs was determined using liquid chromatography-mass spectrometry and correlated with cell of origin, FL signature (defined by EZB phenotype or BCL2 translocation), transcript profile, and clinical outcome. CDR-located AGSs were observed in 41% to 46% of GCB-DLBCLs but were rare in other DLBCLs. Only CDR-located AGSs of DLBCL with an FL signature were occupied by oligomannose-type glycans. These DLBCLs were termed Mann-type DLBCL. Conversely, the AGSs of the other DLBCLs were either nonglycosylated or occupied by complex-type glycans. Mann-type status was an independent marker of short progression-free survival and overall survival. In contrast, the other GCB-DLBCLs, including those with an FL signature but without AGSs, had the best outcomes. Mann-type DLBCLs overexpressed gene sets of cell growth, survival, and cycling, and underexpressed proinflammatory and apoptotic pathways, irrespective of the presence of concomitant MYC translocations. The acquisition of Mann-type glycans is a highly selective environmental pressure enabling the identification of an aggressive GCB-DLBCL type with origin related to FL. The detection of AGSs in the CDR of GCB-DLBCLs with an FL signature defines Mann-type DLBCLs, refines prognosis, and marks a precise tumor interaction to block early therapeutically.