Combined spectral karyotyping and DAPI banding analysis of chromosome abnormalities in myelodysplastic syndrome

Abstract

Spectral karyotyping (SKY) is a new molecular cytogenetic technique that allows simultaneous visualization of each chromosome in a different color. We have used SKY for comprehensive analysis of 20 myelodysplastic syndromes (MDSs) (13 primary MDSs, 3 therapy-related MDSs, and 4 acute leukemias developed from MDS, including 1 cell line established from a secondary leukemia), previously analyzed by G-banding. To locate the chromosomal breakpoints, DAPI-counterstained band images from all metaphases were transformed to G-band-like patterns. By using SKY, it was possible to identify the origin and organization of all clonal marker chromosomes (mar), as well as the origin of all abnormalities defined as additional material of unknown origin (add) or homogeneously staining regions (hsr) by G-banding. In total, SKY identified the chromosomal basis of 38 mar, add, and hsr, corrected 8 abnormalities misidentified by G-banding, and revealed 6 cryptic translocations in 5 cases. Total or partial chromosomal loss (mainly of -5/5q- and -7/7q-) is the most frequent cytogenetic abnormality in MDS. In 3 of 11 cases with -5/5q- and in 4 of 8 with -7/7q-, lost material was detected by SKY in unbalanced translocations. A total of 60 chromosomal losses were identified by G-banding in 16 cases with multiple chromosome abnormalities involving at least 3 chromosomes. For 26 of these losses (43%), SKY analysis suggested that the losses were not complete, but had been translocated to a variety of partner chromosomes. Moreover, SKY analysis revealed that a ring chromosome in a case of acute leukemia developed from MDS contained three to six segments that originated from chromosome 21 material. Fluorescence in situ hybridization showed the amplification of the AML1 gene on regions derived from chromosome 21, providing the first evidence of amplification involving this gene in MDS. Genes Chromosomes Cancer 26:336-345, 1999.

Mechanisms of gene amplification and evidence of coamplification in drug‐resistant human osteosarcoma cell lines

“…It is noteworthy that in both DX-and MTX-resistant variants, amplification of MLL started at the wild-type location on the apparently intact chromosome 11, which is consistent with the findings of a recent FISH analysis of various forms of MLL amplification in 29 patients with transforming MDS or acute myeloid leukemia (AML) (Papenhausen et al, 2005). Similar to our findings in MTX-resistant variants, ladderlike amplification of MLL on chromosome 11 has been reported in a case of myelodysplastic syndrome (MDS) (Kakazu et al, 1999).…”

Characterization of complex chromosomal abnormalities in B-cell lymphoma by a combined spectral karyotyping (SKY) analysis and fluorescence in situ hybridization (FISH) using a 14q telomere probe

“…Cytogenetic analysis of the bone marrow cells showed the following highly complex chromosomal abnormalities: 44-48, X, −X[19], del(1)(p11) [16], −2 [15], add(2)(p13) [12], +der(5)t(1;5)(p13;q31) [12], add(6)(p21.3)[19], del(7)(p13p15) [12], −9 [7], del(10)(q24) [17], −13 [12], −14 [16], add(14)(p10) [12], add(19)(q13.4)[19], −21[19], +mar1 [15], +mar2 [16], +mar3 [7], +mar4 [15], +mar5 [19] [cp19] (Fig. 1).…”

“…Briefly, a SkyPaint kit (Applied Spectral Imaging, Migdal Ha'Emek, Israel), which contains all 24 combinatorially labeled painting probes specific for each human chromosome, was used for hybridization. Hybridization and detection were carried out as described elsewhere [6,7]. Chromosomes were counterstained with DAPI/antifade solution.…”

Variable manifestation in natural killer cell leukaemia

“…Cell harvesting, fixation and trypsin-Giemsa banding were performed using standard methods. For more precise analysis, samples from cases 1, 3 and 4 were subjected to SKY, performed as described previously (Kakazu et al, 1999;Kuroda et al, 2000;Kimura et al, 2001). Karyotypes were reported according to the International System for Human Cytogenetic Nomenclature (Mitelman, 1995).…”