Test Directory

• CBFB, 16q22
• MYH11, 16p13.1

Acute myeloid leukemia (AML) with CBFB::MYH11 fusion is characterized by fusion of the core-binding factor subunit beta (CBFB) and the myosin heavy chain 11 (MYH11) genes. This AML type comprises 5-8% of cases in younger adult patients and decreases in incidence in older adults. The most common cytogenetic alteration, inv(16)(p13.1q22.1), detected in 95% of patients, may be difficult to identify with conventional karyotyping . Secondary chromosomal aberrations are present in 45% of the AML cases with CBFB::MYH11 and include del(7q) (5%) and trisomies 8 (10-20%), 21 (5%) and 22 (15-25%). Somatic mutations are detected in >90% of cases and commonly involve NRAS (30-50%) and KRAS (10-15%), followed by KIT, ASXL2, ASXL1, NF1, TET2, EZH2, FLT3 tyrosine kinase domain, and FLT3 internal tandem duplication. The prognosis of AML with CBFB::MYH11 is favorable, with long-term survival rates of ~50% in adults. FISH for abnormalities of chromosome CBFB::MYH11, inv(16) can be performed on interphase or metaphase cells.

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

• FISH Inversion 16
• CBFB/MYH11
• inv(16)
• Core-Binding Factor Subunit Beta/Myosin Heavy Chain 11