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

Abstract

We report a case of non-Hodgkin's lymphoma of unknown origin with invasion into bone marrow and brain. This case showed complex chromosomal abnormalities, including five clonal marker chromosomes (mar) and four additional materials of unknown origin (add) that could not be identified by means of conventional G-banding. Spectral karyotyping (SKY) analysis could not only determine the origin and organization of all thus far unidentified structural chromosomal abnormalities but also detect two cryptic unbalanced translocations, which had been erroneously considered to be normal on the basis of G-banding analysis, and correct one abnormality misidentified by G banding. Among these abnormalities, we identified the new partner site of the 14q32 translocation, 22q13, and the jumping translocations involving 2p23 as a new donor chromosome. Furthermore, by using fluorescence in situ hybridization (FISH) with the probes specific for the 14q telomere, we could identify the unbalanced translocation of t(3;14)(q27;q32), which had been erroneously considered to be normal chromosome 3 on the basis of not only G-banding but also of SKY analysis. This translocation is one of the most frequent chromosomal abnormalities in B-cell lymphoma, especially diffuse large cell lymphoma. After SKY and FISH analysis, the original descriptions in the G-band karyotype were modified for a total of 13 chromosomes. The combination of SKY and FISH using the 14q telomere probe was therefore considered very useful for the characterization of complex cytogenetic cases in B-cell lymphoma.

A novel infant acute lymphoblastic leukemia cell line with MLL-AF5q31 fusion transcript

“…17 For exact determination of the karyotype of KP-L-RY, fluorescence in situ hybridization (FISH) analysis was performed as previously described. 18 The probes used in this study were two bacterial artificial chromosome (BAC) clones (RP11-115L24 located at chromosome band 5q21.1 and RP11-772D18 containing 5Ј region of the AF5q31 gene), yeast artificial chromosome (YAC) clone 13HH4 containing the MLL gene, and ␣-satellite probe specific for the centromere region of chromosome 11 (D11Z1). Two BAC clones were obtained from the RP11 library.…”

ABL gene fuses BCR during t(20;22) results in Philadelphia-negative, but BCR/ABL-positive chronic myeloid leukemia

“…Dual-color FISH analysis demonstrated a BCR-ABL fusion signal on one chromosome 22, a normal green ABL signal and a normal red BCR signal on one chromosome 9 and the other chromosome 22, respectively (Figure 1d). Karyotyping by SKY 9 showed t(20;22) without detectable segmental translocation of the 9q34 region (Figure 1b). She was given hydroxyurea for about 2 months, and then was given interferon-alpha after being found positive for major BCR-ABL by RT-PCR analysis.…”