BCL6 and diffuse large B-cell lymphoma: However, an analysis of BCL6 mutant alleles from DLBCL tumors and normal GCB cells show a toward for mutations within the first non-coding exon of BCL6 in DLBCL, which could disrupt its circuit of negative autoregulation by preventing BCL6 from binding its own promoter (Wang et al., 2002; Pasqualucci et al., 2003; Figure 1C).