XL t(14;20) IGH/MAFB DF consists of a green-labeled probe hybridizing to the IGH gene region at 14q32.3 and an orange-labeled probe hybridizing to the the MAFB gene and flanking regions at 20q12.

Probe maps are created in accordance with the intended purpose of the product. Solid colored bars do not necessarily indicate that the probe fully covers the indicated genomic region. Therefore, caution is advised when interpreting results generated through off-label use. Probe map details based on UCSC Genome Browser GRCh37/hg19. Map components not to scale. Further information is available on request.

The most frequent primary abnormalities in multiple myeloma (MM) are trisomies of odd-numbered chromosomes or translocations involving the immunoglobulin heavy chain (IGH) gene locus. The most common MM-associated IGH translocations are t(11;14), t(4;14), t(6;14), t(14;16) and t(14;20) in the order of their occurrence. As a consequence, translocation partner genes of IGH are dysregulated, as they are juxtaposed to transcriptional enhancers in the IGH locus. Prognosis and risk classification are strongly associated with the detection and interpretation of cytogenetic primary abnormalities. According to the International Myeloma Working Group (IMWG), risk classification of MM by FISH based analysis of IgH locus involving translocations represents one column of the entire diagnostics. Secondary effects are also influencing the outcome. Even if associated with poor prognosis in MM, MGUS/SMM cases characterized by the presence of t(14;20) can be stable for years before progression occurs, whereas MGUS/SMM cases with t(4;14) and t(14;16) show a significantly faster progression rate. The recurrent translocation t(14;20) (q32;q12) results in ectopic expression of the basic leucine zipper transcription factor MAFB (Vmaf musculoaponeurotic fibrosarcoma oncogene homolog B) which plays an important role in lineage-specific hematopoiesis. Furthermore, t(14;20) is associated with poor prognosis by promoting high cyclin D2 activity, thereby dysregulating normally balanced cell cycle.

Clinical Applications

• Multiple Myeloma and Plasma Cell Neoplasms (MM)

XL IGH/MAFB DF hybridized to bone marrow cells, one aberrant cell is shown. A translocation t(14;20) has occurred generating a signal pattern of two colocalization/fusion signals, one green and one orange signal.

• Boersma-Vreugdenhil et al (2004) Brit J Haem 126:355-363
• Ross et al (2010) Haematologica 95:1221-1225
• Rajan and Rajkumar (2015) Blood Cancer J 5:e365