title: Dissecting karyotypic patterns in non-hyperdiploid multiple myeloma: an overview on the karyotypic evolution.
abstract: BACKGROUND
  Multiple myeloma (MM) is a plasma cell disorder characterized by the presence of specific genetic and cytogenetic aberrations that define unique subgroups with different outcomes. On the basis of the ploidy status, MM can be subdivided into hyperdiploid MM (H-MM) and non-hyperdiploid MM (NH-MM). NH-MM is an entity that encompasses hypodiploid, pseudodiploid, and near tetraploid MM and is associated with a higher number of immunoglobulin heavy-chain (IgH) translocations.
  
  
  METHODS
  We have systematically analyzed the structure of the karyotypic evolution in NH-MM and identified several genetic features of their complex karyotypic patterns.
  
  
  RESULTS
  On the basis of statistical models used in complex karyotypes, we were able to identify the temporal order in which the genetic aberrations occur in NH-MM. In this analysis, whole chromosome losses and IgH translocations were commonly seen, and -13/13q- and t14q32 were defined as early genetic events in the karyotypic evolution of NH-MM. Furthermore, chromosome 1 and 17 abnormalities were associated with a late karyotypic phase of evolution consistent with the recognized pattern of acquired events deemed to be associated with these type of genetic aberrations.
  
  
  CONCLUSIONS
  Accumulation of genetic aberrations in NH-MM above a threshold results in malignant transformation.
authors.affiliation: Princess Margaret Hospital, Department of Medical Oncology and Hematology, Toronto, ON, CA.
authors.forename: Victor H
authors.initials: VH
authors.lastname: Jimenez-Zepeda
authors.forename: Esteban
authors.initials: E
authors.lastname: Braggio
authors.forename: Rafael
authors.initials: R
authors.lastname: Fonseca
mesh_terms: D002869:Chromosome Aberrations; D056905:Chromosome Breakpoints; D016000:Cluster Analysis; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D059785:Karyotype; D007621:Karyotyping; D009101:Multiple Myeloma / Q000235:genetics*; D011003:Ploidies; D014178:Translocation, Genetic
chemical_list: D007143:Immunoglobulin Heavy Chains
keywords: Cytogenetics; Multiple myeloma; Time to occurrence