BCL6 and aneurysmal bone cyst: The GCB-DLBCLs express genes characteristic of normal germinal center B cells such as CD10 and BCL6, and have ongoing somatic hypermutations (SHMs) of the immunoglobulin V genes, while the ABC-DLBCLs express genes characteristic of in vitro activated B cells, and do not express germinal center B cell-restricted genes or have ongoing SHMs.