Test Directory

• IGH, 14q32.3
• MAFB, 20q12

Plasma cell myeloma (PCM) is a complex and genetically heterogenous hematological malignancy involving clonal proliferation of plasma cells in bone marrow. Standard karyotype and fluorescence in situ hybridization (FISH) evaluation of bone marrow is required in the initial diagnostic workup to risk stratify patients based on their cytogenetic status. Primary cytogenetic events are classified as either hyperdiploid or non-hyperdiploid. Common in non-hyperdiploid cases is rearrangement of the immunoglobulin heavy chain (IGH) gene on chromosome 14q32.33, most commonly with the cell-cycle regulator cyclin D1 (CCND1) gene at 11q13.3, and to a lesser extent fibroblast growth factor receptor 3 (FGFR3)/multiple myeloma SET domain (MMSET) genes at 4p16.3 or the MAF gene at 16q23.2. The rarest of these IGH translocations involves the MAFB gene at 20q12. Approximately 40-50% of myeloma cases demonstrate an IGH gene rearrangement. The t(14;20)(q32;q12) is the rarest of the five most common IGH-rearrangements, found in approximately 1% of cases [Manier et al, 2016].

• 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 orange signals and two green signals. In an abnormal cell containing a typical translocation, the expected signal pattern is one orange signal, one green signal, and two fused signals.

• FISH Translocation IGH/MAFB
• t(14;20)