Test Directory

IGL, 22q11.21-q11.23

The immunoglobulin (IG) genes for the kappa light chain at 2p11 (IGK), the lambda light chain at 22q11 (IGL) and the heavy chain at 14q32 (IGH) are recurrently involved in the development of non-Hodgkin lymphomas (NHL). By far most frequently involved is IGH with more than 30 partner genes, less frequently IGK and IGL. IG-translocations are leading to juxtaposition of proto-oncogenes with IG enhancer sequences resulting in overexpression of the respective oncogene. Chromosomal translocations involving MYC at 8q24 and IG genes frequently occur in Burkitt lymphoma (BL). BL is a rare but fast growing type of NHL which is rapidly fatal if left untreated. About 75% of BL patients are carrying the MYC rearrangement t(8;14) while the remainder show a translocation between MYC and IGK or IGL. MYC-IG rearrangements are also involved in other B-cell malignancies such as atypical Burkitt/Burkitt-like lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma and multiple myeloma. Besides 8q24 (MYC), other translocation partners for IGK including chromosomal regions 1p13, 3q27 (BCL6), 7q21, 16q24 and 18q21 (BCL2).

FISH break apart assays are valuable tools for the detection of IG light chain rearrangements independent of the translocation partner. Furthermore, double translocations have been described which are difficult to detect by PCR-based methods.

Specimen: Formalin-Fixed Paraffin Embedded (FFPE) Tissue Block or 2 slides from FFPET block, cut at 4 micron thickness and mounted on charged lysine slides with accompanying H&E slide indicating the region(s) of interest (ROI), if the entire specimen is not tumor.

Specimens should have an ischemia time of < 1 hour and a formalin fixation time of

6 - 72 hours.

Transport to the laboratory at room temperature.

• Specimen arriving without any form of patient identification (unlabeled)
• FFPET sections that are not properly attached to the slide
• FFPET sections with excessive cracks, splits or deterioration that would inhibit analysis
• Broken FFPET slides

In a normal cell, the expected signal pattern is two fusion signals. In an abnormal cell containing a rearrangement, the expected signal pattern is one red signal, one green signal, and one fusion signal.

• FISH IGL Breakapart, Tissue
• IGL BA
• IGL
• Immunoglobulin Lambda Locus