The IGK product consists of a 183kb probe, labelled in red, covering a part of the distal IGK Variable region and a green probe, covering a 606kb region telomeric to the Joining segments and the Constant segment of IGK, between the D2S2216 and D2S2510 markers.
Translocations involving the immunoglobulin loci are recurring events in various subtypes of B-cell lymphomas.
In addition to translocations involving the IGH locus, variant translocations have been described in 5-10% of B-cell neoplasms involving either the immunoglobulin kappa (IGK) light chain locus at 2p11.2 or the lambda light chain (IGL) at 22q111,2. The best known translocations involving IG light chain loci are the variant Burkitt's translocations t(2;8)(p12;q24) and t(8;22)(q24;q11) present in up to 21% of all Burkitt's lymphomas3. Other translocations involve the BCL6 oncogene: the t(2;3)(p12;q27) and t(3;22)(q27;q11) and BCL2 locus: t(2;18)(p12;q21) and t(18;22)(q21;q11)5.
Translocations involving the IG light chain loci usually lead to breakage within the joining region of the respective locus2. IGK has a largely duplicated structure with duplicate gene regions being 96-100% identical. The IGK proximal copy is present in a 542kb contig with 22 potentially functional variable (IGKV) gene segments and 18 pseudogenes plus five joining (J)- segments and one IGK constant (IGKC) gene segment. The distal copy is a 433kb contig with 21 potentially functional IGKV gene segments and 15 pseudogenes. The two contigs are separated by a DNA sequence of 800kb without any IGKV segments1.
It was very important for us to have more consistent results with our probes — easy-to-read bright signals and a range of vial sizes, which is much more cost-effective. It also was critical to upgrade our pretreatment kit to expedite the analysis of FFPE samples. We can now complete the process in about 90 minutes.
Janet Cowan, PhD
Director of the Cytogenetics Laboratory, Tufts Medical Center, USA