EVI1 (MECOM) Breakapart
- EVI1, 3q26.2, Texas Red
- EVI1, 3q26.2, FITC Green
- EVI1, 3q26.2, PF-415 Blue
The EVI1 (MECOM) Breakapart FISH Probe Kit consists of a 158kb probe, labeled in Texas Red, telomeric to the D3S4415 marker and including the LRRC34 gene, a FITC green probe covering a 181kb region, including the entire EVI1 (MECOM) gene and flanking regions and a PF-415 blue probe, which covers a 563kb region centromeric to the EVI1 (MECOM) gene, including the D3S1614 marker.
The MECOM (MDS1 and 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 AML and MDS patients1. 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 RPN1 (ribophorin I) 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-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.
The EVI1 (MECOM) Breakapart FISH Probe Kit is a fluorescence in situ hybridization (FISH) Test used to detect rearrangement involving the EVI1 (MECOM) region on chromosome 3 at location 3q26.2, in fixed bone marrow specimens from patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). The test is indicated for characterization of patient specimens consistent with World Health Organization (WHO) guidelines for Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th Edition) and in conjunction with other clinicopathological criteria. The assay results are intended to be interpreted by a qualified pathologist or cytogeneticist. The test is not intended for use as a stand-alone diagnostic, disease screening, or as a companion diagnostic.
Limitations of the Procedure
For In Vitro Diagnostic Use. Rx only.
Reporting and interpretation of FISH results should be consistent with professional standards of practice and should take into consideration other clinical and diagnostic information. This kit is intended as an adjunct to other diagnostic laboratory tests and therapeutic action should not be initiated on the basis of the FISH result alone. Failure to adhere to the protocol may affect the performance and lead to false results.
Each lab is responsible for establishing their own cut-off values. Each laboratory should test sufficiently large number of samples to establish normal population distribution of the signal levels and to assign a cut-off value. The product is for professional use only and is intended to be interpreted by a qualified Pathologist or Cytogeneticist.
For sale in the US only. This product has not been licensed in accordance with Canadian law.
1. Soderholm J et al., Leukemia. 1997;11(3):352–8.
2. Bobadilla D et al., Br J Haematol. 2007;136(6):806–13.
3. Swerdlow et al., (eds,) WHO Classification of Tumours of Haematopoietic and Lymphoid Tissue, Lyon, France, 4th edition, IARC,2017.
4. Pedersen-Bjergaard J et al., Leukemia. England; 2008 Feb;22(2):240–8.
Recommended Protocol and Sample Preparation
- The FISH probes for AML/MDS are designed for use on bone marrow cells fixed in Carnoy’s solution (3:1 methanol/ acetic acid) that are prepared according to the laboratory or institution guidelines.
- Spot the cell sample onto a glass microscope slide. Allow to dry.
- Immerse the slide in 2x Saline Sodium Citrate (SSC) for 2 minutes at room temperature (RT) without agitation.
- Dehydrate in an ethanol series (70%, 85% and 100%), each for 2 minutes at RT.
- Allow to dry.
- Remove the probe from the freezer and allow it to warm to RT. Briefly centrifuge tubes before use.
- Ensure that the probe solution is sufficiently mixed with a pipette or a vortex mixer.
- Remove 10μl of probe per test, and transfer it to a microcentrifuge tube. Quickly return the remaining probe to -20°C.
- Place the probe and the sample slide to prewarm on a 37°C (+/- 1°C) hotplate for 5 minutes.
- Spot 10μl of probe mixture onto the cell sample and carefully apply a 24x24 mm coverslip. Seal with rubber solution glue and allow the glue to dry completely.
- Denature the sample and probe simultaneously by heating the slide on a hoplate at 75°C (+/- 1°C) for 2 minutes.
- Place the slide in a humid, lightproof container at 37°C (+/- 1°C) overnight.
- Remove the DAPI from the freezer and allow it to warm to RT.
- Remove the coverslip and all traces of glue carefully.
- Immerse the slide in 0.4x Saline Sodium Citrate (SSC) (pH 7.0) at 72°C (+/- 1°C) for 2 minutes without agitation.
- Drain the slide and immerse it in 2xSSC + 0.05% Tween-20 at RT (pH 7.0) for 30 seconds without agitation.
- Drain the slide and apply 10μl of DAPI antifade onto each sample.
- Cover with a 24x24mm coverslip, remove any bubbles.
- Edge the slide with clear nail varnish to seal.
- Allow the color to develop in the dark for 10 minutes.
- View with a fluorescence microscope.
- For optimal visualization of the probes, a 100-Watt mercury lamp (or equivalent) is recommended with plan apochromat objectives 63x or 100x.
- Filters designed specifically for detection of DAPI, FITC, Texas Red®, and Aqua or DEAC fluorophores individually or in combination (e.g. dual or triple filters) are optimal for best results.
- The final hybridized slides are analyzable for up to 1 month when stored in darkness and at 2-8°C.
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