Abstracts of Annual Education Meeting on 25-Nov-2002
Cytogenetics Of Multiple Myeloma
Fiona Ross
The low mitotic indices of malignant plasma cells coupled with the complexity of karyotypes when they are found has meant that it has been difficult to determine the relevance of chromosome abnormalities either to the development of myeloma or to prognosis. However, fluorescence in situ hybridisation (FISH) now allows information on chromosome changes to be obtained in the absence of relevant mitoses and this has led to an explosion of cytogenetic information in myeloma.
At present much of the emerging results are contradictory so that the precise significance of the various abnormalities is still uncertain. Loss of all or part of chromosome 13 appears to be a poor prognostic indicator, although there is still some conflict on how strong its prognostic effect is, and whether it has a role to play in development of myeloma from MGUS.
The only current candidate for a possible primary or causative chromosome change is translocation involving the immunoglobulin heavy chain locus on chromosome 14. Although there are large numbers of partner chromosomes involved in such translocations it may be possible to simplify these into a small number of genuine primary abnormalities, with the majority of the rest being later, less important changes. Some clinical characteristics are emerging for the so-called primary translocations. However, there are still significant numbers of patients from whom no good candidate primary abnormality is recognised.