Test Directory

MECOM (EVI1), 3q26.2

The MECOM [myelodysplasia syndrome 1 (MDS1)and ecotropic virus integration site 1 protein homolog (EVI1) complex locus] oncogene at 3q26.2 is often rearranged in hematological malignancies of myeloid origin. MECOM encodes a zinc finger protein that is inappropriately expressed in the leukemic cells of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) patients. This deregulated expression is often due to a chromosomal rearrangement involving 3q26.2, with the two most common aberrations being the t(3;3)(q21;q26.2) and inv(3)(q21q26.2)1. The breakpoints for the translocations and inversions vary considerably. Inversion breakpoints are found centromeric to, and include the MECOM gene, covering about 600kb. The majority of breakpoints in 3q26.2 translocations are telomeric to the MECOM gene and cover a region including the telomeric end of the MDS1 gene and the MYNN gene2. Chromosome rearrangements involving the 3q26.2 region are associated with myeloid malignancies, aberrant expression of MECOM gene and an unfavorable prognosis2. AML with inv(3)(q21q26.2) or t(3;3)(q21;q26.2) is a recognized disease entity according to the World Health Organization (WHO) classification of myeloid neoplasms and acute leukemia. This is a transformed or de novo AML with a very aggressive clinical course and aberrations that involve MECOM at 3q26.2 and ribophorin I (RPN1) at 3q213. MECOM has also been shown to be rearranged in therapy-related disease via the t(3;21)(q26.2;q22) translocation, resulting in a MECOM-runt-related transcription factor 1 (RUNX1) fusion3,4. MECOM rearrangements are very heterogeneous and may be difficult to detect by conventional cytogenetics, making FISH a useful tool for their detection.

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 translocation, the expected signal pattern is two fusions and one red signal. In an abnormal cell containing an inversion, the expected signal pattern is two fusions and an aqua signal.

• FISH EVI1 Breakapart
• FISH MECOM Beakapart
• EVI1 BA
• MECOM BA
• EVI1
• MECOM