Test Directory

• RB1, 13q14.2
• DLEU, 13q14.2
• LAMP, 13q34

Cytogenetic studies using chromosome analysis and interphase fluorescence in situ hybridization (FISH) are routine procedures for prognostic stratification of plasma cell myeloma. Cytogenetic abnormalities are both numerical and structural and include trisomies, whole or partial chromosome deletions and gains and chromosomal translocations. About half of multiple myeloma tumors are hyperdiploid with 48 to 75 chromosomes and have gains of three or more of the odd-numbered chromosomes 3, 5, 7, 9, 11, 15, 19, and 21. The other half of multiple myeloma tumors are mostly non-hyperdiploid with <48 or >75 chromosomes and usually have an immunoglobulin heavy chain (IGH) translocation at chromosome 14q32. Common secondary cytogenetic abnormalities in multiple myeloma (MM) include deletion of chromosome 13q (or monosomy 13) found in about 50%, deletion of chromosome 17p including TP53 (or monosomy 17) found in about 10%, deletion of 1p found in about 20%, and duplication or amplification of 1q found in about 40% of MM. In addition, MYC locus translocations are also present in about 40% of multiple myeloma. These reposition MYC near a promiscuous array of PC specific super enhancers (including immunoglobulin heavy chain (IGH), immunoglobulin kappa locus (IGK), immunoglobulin lambda locus (IGL) and non-Ig enhancers) MYC translocations can contribute to progression from monoclonal gammopathy of unknown significance (MGUS) to multiple myeloma.

Bone marrow samples used for plasma cell neoplasia testing are sorted for CD138 positive selection cells using magnetic beads. FISH analysis on the CD138 positive selected cells has been shown to increase diagnostic sensitivity. In cases with inadequate /insufficient sample, CD138+ enrichment will not be attempted.

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 orange signals, two green signals and two aqua signals. In an abnormal cell containing the deletion, the expected signal patterns are one green signal, two orange signals, and two aqua signals or one green signal, one orange signal, and two aqua signals.

• FISH Deletion RB1/DLEU/LAMP 13q
• Retinoblastoma 1