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 include 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 Types: Leukemic Blood or Bone Marrow

Preferred Collection Container: Green Top (Sodium Heparin)

Alternate Collection Container: Lavendar Top (EDTA)

Desired Specimen Volume: 3 - 5 mL

Minimum Acceptable Volume: 1 mL

• Lithium heparin is not acceptable.
• Specimens must be collected in a sterile collection container.

Each specimen must be accompanied by a requisition form, script, electronic order or physician note. Each order must indicate the reason for testing (diagnosis).

• Transport to the laboratory at room temperature.
• Store specimen as whole blood, in original tube, at room temperature and deliver to lab within 24 hours.
• If specimen cannot be delivered within 24 hours, store in refrigerator. Do not freeze specimen.
• Specimens collected on the weekends must be refrigerated upon arrival at HNL Lab Medicine.

• Specimen frozen
• Specimen arriving without any form of patient identification (unlabeled)
• Specimen with attached needles
• Specimen arriving with broken or leaking collection tube
• Unfixed specimen treated with fixative

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, Heme
• IGL BA
• IGL
• Immunoglobulin Lambda Locus