Duplication of chromosome arms 9q and 11q: evidence for a novel, 14q32 translocation-independent pathogenetic pathway in multiple myeloma

Cytogenetics and molecular cytogenetics in multiple myeloma

Multiple myeloma (MM) is characterized by frequent and complex genomic abnormalities that not only essentially contribute to the pathogenesis of this disease but also reflect its prognostic heterogeneity. There is evidence for two more or less mutually exclusive oncogenic pathways in the early development of clonal plasma cell disorders. Approximately half the tumours are non-hyperdiploid and carry translocations of the immunoglobulin heavy-chain (IgH) locus and various oncogenes, for example Cyclin D1, Cyclin D3, and FGFR3. The remaining hyperdiploid tumours exhibit recurrent trisomies - typically of chromosomes 5, 7, 9, 11, 15, 19, and 21 - but infrequently exhibit IgH translocations. While some chromosomal aberrations, such as deletion of chromosome arm 13q, deliver independent prognostic information that is already utilized for risk stratification within clinical trials, the prognostic significance of most other genetic aberrations in MM is undetermined.

Frequent gain of chromosome band 1q21 in plasma-cell dyscrasias detected by fluorescence in situ hybridization: incidence increases from MGUS to relapsed myeloma and is related to prognosis and disease progression following tandem stem-cell transplantation

Using fluorescence in situ hybridization we investigated amplification of chromosome band 1q21 (Amp1q21) in more than 500 untreated patients with monoclonal gammopathy of undetermined significance (MGUS; n = 14), smoldering multiple myeloma (SMM; n = 31), and newly diagnosed MM (n = 479) as well as 45 with relapsed MM. The frequency of Amp1q21 was 0% in MGUS, 45% in SMM, 43% in newly diagnosed MM, and 72% in relapsed MM (newly diagnosed versus relapsed MM, P < .001). Amp1q21 was detected in 10 of 12 patients whose disease evolved to active MM compared with 4 of 19 who remained with SMM (P < .001). Patients with newly diagnosed MM with Amp1q21 had inferior 5-year event-free/overall survival compared with those lacking Amp1q21 (38%/52% versus 62%/78%, both P < .001). Thalidomide improved 5-year EFS in patients lacking Amp1q21 but not in those with Amp1q21 (P = .004). Multivariate analysis including other major predictors revealed that Amp1q21 was an independent poor prognostic factor. Relapsed patients who had Amp1q21 at relapse had inferior 5-year postrelapse survival compared with those lacking Amp1q21 at relapse (15% versus 53%, P = .027). The proportion of cells with Amp1q21 and the copy number of 1q21 tended to increase at relapse compared with diagnosis. Our data suggest that Amp1q21 is associated with both disease progression and poor prognosis.