Genomic instability in multiple myeloma: evidence for jumping segmental duplications of chromosome arm 1q.
Multiple myeloma (MM) is a malignant plasma cell disorder characterized by complex karyotypes and chromosome 1 instability at the cytogenetic level. Chromosome 1 instability generally involves partial duplications, whole-arm translocations, or jumping translocations of 1q, identified by G-banding. To characterize this instability further, we performed spectral karyotyping and fluorescence in situ hybridization with probes for satII/III (1q12), BCL9 (1q21), and IL6R (1q21) on the karyotypes of 44 patients with known 1q aberrations. In eight patients, segmental duplication of 1q12-21 and adjacent bands occurred on nonhomologous chromosomes. In five cases, the 1q first jumped to a nonhomologous chromosome, after which the 1q12-21 segment again duplicated itself 1-3 times. In three other cases, segmental duplications occurred after the 1q first jumped to a nonhomologous chromosome, where the proximal adjacent nonhomologous chromosome segment was duplicated prior to the 1q jumping or inserting itself into a new location. These cases demonstrate that satII/III DNA sequences are not only associated not only with the duplication of adjacent distal chromosome segments after translocation, but are also associated with the duplication and jumping/insertion of proximal nonhomologous chromosome segments. We have designated this type of instability as a jumping segmental duplication.
Sawyer
Jeffrey R
JR
Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA. sawyerjeffreyr@uams.edu
Tricot
Guido
G
Lukacs
Janet L
JL
Binz
Regina Lichti
RL
Tian
Erming
E
Barlogie
Bart
B
Shaughnessy
John
J
D000328:Adult; D000368:Aged; D002871:Chromosome Banding; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics*; D005260:Female; D020440:Gene Duplication; D042822:Genomic Instability / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000235:genetics*