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FISH detection of chromosome 14q32/IgH translocations: evaluation in follicular lymphoma
Author(s) -
Rack Katrina A,
SalomonNguyen Florence,
RadfordWeiss Isabelle,
Ocana Gil Maria,
Schmitt Christian,
Belanger Coralie,
Nusbaum Sylvie,
Vekemans Michel,
Valensi Françoise,
Macintyre Elizabeth A
Publication year - 1998
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.1998.01009.x
Subject(s) - cosmid , biology , chromosomal translocation , locus (genetics) , follicular lymphoma , microbiology and biotechnology , karyotype , fluorescence in situ hybridization , gene rearrangement , immunoglobulin heavy chain , genetics , chromosome , lymphoma , gene , immunology
A FISH strategy capable of detecting chromosome 14q32 rearrangements involving the IgH locus, including in interphase nuclei, was developed using Ig variable and constant region cosmids from the extremities of the locus in a dual hybridization approach, using signal splitting as evidence of rearrangement. The large size of the locus (1.3 Mb) and the propensity for internal deletion due to physiological VDJ recombination and isotype switching complicate analysis of this locus. We used the Ig10 cosmid, which hybridizes to Cε and Cα2 at the 3′ end of the constant region, in order to minimize deletion and/or splitting of the constant region probe. Cos Ig10 and the IgV18 VH probes were compared with a specific IgH‐BCL2 FISH dual hybridization approach in follicular lymphoma (FL). Both were capable of detecting the t(14;18) in interphase nuclei, including in cases with no apparent abnormality by classic karyotype analysis, although the sensitivity of the IgH approach was slightly lower. We have also successfully applied these probes to whole cell cytospin preparations, rendering analysis of cryopreserved material possible, although interpretation should be limited to frequent events, particularly following cell manipulation. Analysis of flow cytometric sorted bone marrow fractions from three FL patients by FISH and FICTION showed that the t(14;18) was present in a much lower proportion of CD34 positive than negative cells but that the higher level of background hybridization limits use of these techniques for the reliable quantification of rare events.