New recurrent chromosome alterations in patients with multiple myeloma and plasma cell leukemia

Chromosome abnormalities detected in metaphases from multiple myeloma (MM) cells have a clear impact on prognosis and response to therapy. Thirteen out of 50 (26%) patients with plasma cell disorders and abnormal karyotypes (11 with MM and 2 with plasma cell leukemia (PCL)) were selected for inclusion in the present report based on the presence of karyotypes with new and/or infrequent structural aberrations. Thirty-three new rearrangements, including a novel recurrent aberration: psu dic(5;1)(q35;q10), were detected. Chromosome 1 was the most frequently involved. Gains of genetic material (57%) were noted more frequently than losses (43%). Three rearrangements that were observed only once in the literature appear to be recurrent from our data: del(16)(q13), del(5)(p13) and i(3)(q10), the latter being a single structural aberration in the karyotype. Clinical parameters from our series were compared with 2 control groups: 20 MM cases with recurrent aberrations in MM/PCL with a similar distribution of abnormalities associated with poor prognosis (group 1), and 40 with normal karyotypes and fluorescence in situ hybridization analysis (group 2). Significantly increased serum calcium levels (p = 0.022) in patients with new and/or infrequent chromosome changes with respect to both control groups, and a higher percentage of bone marrow plasma cell infiltration (p = 0.005), β(2) microglobulin, and lactate dehydrogenase levels (p < 0.0001) compared to group 2 were observed. Our results suggest that some of these novel rearrangements may be capable to deregulate genetic mechanisms related to the development and/or progression of the disease. The finding of new recurrent aberrations supports this hypothesis.