The most frequent primary abnormalities in multiple myeloma (MM) are trisomies of odd-numbered chromosomes or translocations involving the immunglobulin 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. The consequence of these rearrangements is the dysregulation of genes juxtaposed to transcriptional enhancers in the IGH locus. Prognosis and risk stratification strongly depends on the detection and interpretation of cytogenetic primary abnormalities. t(14;16) and t(14;20) are considered as high risk, t(4;14) as intermediate risk, and t(6;14) and t(11;14) as standard risk cytogenetic aberrations in patients with MM based on FISH testing. Secondary aberrations are also influencing the outcome.
Even if associated with poor prognosis in MM, monoclonal gammopathy of undetermined significance/smoldering multiple myeloma (MGUS/SMM) cases characterized by t(14;20) can be stable for years before progression occurs, whereas MGUS/SMM cases with t(4;14) and t(14;16) are showing a higher progression rate. The recurrent t(14;20) results in ectopic expression of the basic leucine zipper transcription factor MAFB which has an important role in lineage-specific hematopoiesis.
Clinical Applications
- Multiple Myeloma and Plasma Cell Neoplasms (MM)