Major breakpoint duster

Figure 39-8 Schematic representation of the organization of the 6CL-2 gene and most frequent breakpoints on chromosome I8q2l involved in the t( 14 18).The 6CL-2 exons are represented as rectangles. MBR represents the major breakpoint duster region where approximately 50% to 60% of the breakpoints occur. MCR represents the minor breakpoint duster region where 20% to 25% of the breakpoints may be found.VCR represents the variant duster region where 5% to 20% of the breakpoints may be found.

Figure 39-14 Schematic representation of the BCR (22q 11) and ABL (9q34) genes involved in the t(9 22), which is characteristic of all CMLs and a subset of ALLs. The centromeric (cen) and teiomeric (tel) directions are indicated.The relative positions of the major breakpoint duster (M-BCR), the minor breakpoint duster (m-6CR), and the micro breakpoint duster regions (ft-BCR) are shown. The previously used alternative nomenclature for the BCR and ABL exons is included where relevant. In panel A, the exons of the BCR genes are depicted in black rectangles, and those of the ABL genes are depicted in white rectangles. In panel B, the configuration and varieties of the BCR-ABL chimeric fusions seen in CML are shown. In the lower part of panel B, the configuration and varieties of the BCR-ABL fusions seen in ALL are shown. The el-a2 transcript is most commonly detected in t(9 22)-positive ALL, while the b3-a2 and b2-a2 fusions are the most commonly detected in CML...

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