BCL6 and diffuse large B-cell lymphoma: GCB DLBCL is derived from normal germinal center B cells and is characterized by the expression of CD10, a cell membrane zinc-dependent metalloendopeptidase, and BCL6, a transcription factor regulating T follicular helper cells (TFH cells) proliferation with clinical significance in lymphomas, and also by BCL2 gene rearrangements.