Chromosome translocations mediated by B cell specific mechanisms.

Errors in any of three developmentally regulated B cell specific DNA modification processes can mediate IgH or IgL translocations. V(D)J recombination is involved in receptor formation and editing in early B cells in the bone marrow, whereas most IgH switch recombination and all somatic hypermutation occurs in germinal center B cells. Examples of specific translocations mediated by these three mechanisms are indicated. As indicated by the 3q27 bcl-6 NHL notation in this diagram, the bcl-6 oncogene is subject to somatic hypermutation, which can cause either mutations that dysregulate or structurally alter this gene, or double-stranded breaks that can mediate translocations that do not involve an Ig locus.