Test Directory

IRF4, 6p25

The updated (2016) revision of the World Health Organization (WHO) classification of tumors of lymphoid neoplasms considers the large B-cell lymphoma with interferon regulatory factor 4 or multiple myeloma oncogene-1 (IRF4) rearrangement as a new provisional entity. Chromosomal translocations involving the IRF4 gene and the immunoglobulin heavy chain (IGH), immunoglobulin lambda locus (IGL) and immunoglobulin kappa locus (IGK) result in dysregulation of IRF4 expression. Other translocation partners may occur. Since t(6;14)(p25;q32) is cytogenetically cryptic, FISH is a valuable tool in detecting this recurrent aberration. IG/IRF4 positive lymphomas normally lack t(14;18), which is observed in about 85% of adult patients with follicular lymphoma and are commonly associated with young age and a good course. IRF4 rearrangements have also been identified in peripheral T-cell lymphomas (PTCL). PTCL are defined as a diverse group of aggressive lymphomas of mature-stage T-cells accounting for about 10% of non-Hodgkin lymphomas. Recent data suggests that IRF4 translocations detected by FISH have a predictive value for primary cutaneous CD30(+) anaplastic large cell lymphoma.

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 IRF4 Breakapart, Tissue
• IRF4 BA
• IRF4
• Interferon Regulatory Factor 4
• Multiple Myeloma Oncogene-1