Chromosome Aberrations in 130 Patients with Multiple Myeloma Detected by Interphase FISH and Their Diagnostic and Prognostic Relevance.

Abstract

Recent publications have shown that chromosomal abnormalities in patients with leukemias play an important role with respect to therapy and prognosis. In multiple myeloma (MM) the role of specific cytogenetic changes relevant for the prognosis is still to be defined. Recent data suggest that much more patients show chromosomal aberrations than previously suspected, but differentiation between main and side lines of karyotype evolution was problematic. In the present investigation, cytogenetic analysis was performed using interphase FISH in 130 patients with multiple myeloma. For hybridization, 9 repetitive (chromosomes 3, 7, 9, 11, 15, 17, 18, X, Y) and 7 single copy probes (2x5, 13, 17, 21, 2x22) were used. Aberrations were detected in 87% of the patients. Most cases showed 1–3 aberrations. There was a correlation between the number of aberrations per patient and the tumor stage. E.g. the percentage of patients with 7–12 aberrations increased from 16% in stage II to 28% in stage III. Gains and losses of chromosomes showed significant interchromosomal differences with gains being more frequent than losses. Chromosomes 3, 5, 7, 9, 21 and 22 showed predominantly gains. Losses were found in chromsomes 13, 17, X and Y. But monosomy of sex chromosomes (average age of 63.5 years) may be in part explained by the age of the patients. For chromosomes 15 and 18 a similar number of monosomies and trisomies was found which might be caused by mitotic nondisjunction. Deletions 13q14 (28%), gain of 11q13 and translocation of IgH locus 14q32 (79%) are specific aberrations detected in 39 patients analysed with specific DNA probes of the relevant loci. All three aberrations led to modified survival times of the patients. Summarizing our results in 130 patients with MM, we found that the number of numerical chromosomal aberrations as well as selected structural aberrations proved to be of diagnostic and prognostic relevance.