Biological features of aggressive B-cell lymphomas and relationship to cell of origin derivation. Aggressive B-cell lymphomas comprise a spectrum of diseases ranging from DLBCL-NOS to HGBL to BL. While all cases of BL harbor a MYC rearrangement and all cases of HGBL-DH/THL harbor MYC and BCL2 and/or BCL6 rearrangements, other cases with high-grade morphology harbor varying combinations of rearrangements. BL is derived from a germinal center B-cell (GCB) origin and most HGBL cases are also of GCB derivation; DLBCL-NOS may be of GCB or ABC origin.