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Del(7q) Deletion

Applications
haematology
Catalogue Numbers
LPH 025-S (5 tests)
LPH 025 (10 tests)

Probe Specification

  • 7q22.1-q22.2, Red
  • 7q31.2, Green

The 7q22 probe, labelled in red, covers a 396kb region including the telomeric end of the RELN gene and extending beyond the marker D7S658. The 7q31 probe, labelled in green, covers a 203kb region including the TES gene.

Probe Information

Monosomy of chromosome 7 and deletions of the long arm of chromosome 7 are recognised recurrent chromosomal aberrations frequently seen in myeloid disorders.

Monosomy 7 and del(7q) are seen in a number of myeloid disorders, including myelodysplastic syndrome (MDS), acute myeloid leukaemia (AML), and juvenile myelomonocytic leukemia (JMML)1. Furthermore, it occurs in MDS and AML that develop in patients with constitutional disorders (eg, Fanconi anaemia, Kostmann syndrome, neurofibromatosis type 1, and familial monosomy 7)2. The presence of Monosomy 7 or del(7q) as karyotypic changes are associated with a poorer outcome in myeloid malignancies1,3.

Deletions of chromosome 7 are typically large with heterogeneity in the breakpoints in myeloid diseases, making it difficult to map the common deleted regions (CDRs). It is highly likely that multiple tumour suppressor genes on chromosome 7 cooperate in leukaemogenesis4. Two CDRs have been previously reported: one at 7q22 and the other on 7q31-q362,5, which are both targeted by this probe set.

I first came across Cytocell FISH probes in a previous lab I worked in and I was struck by the quality of the products. Since this time, I have been recommending and introducing Cytocell probes across all application areas — now they are the primary FISH probes used in our lab. They have an excellent range of products and their ready-to-use reagent format saves considerable time. As a matter of fact, at a recent conference there was a discussion about the lack of commercial probes for a particular disorder and I was happy to point the participants in the direction of the Cytocell catalogue, which contains the exact probes required. Elizabeth Benner, Medical Technologist at the University of Arizona Health Network

References

  1. Jerez et al., Blood 2012;119(25):6109-6118
  2. Fisher et al., Blood 1997;89(6):2036-2041
  3. Trobaugh-Lotrario et al., Bone Marrow Transplantation 2005;35(2):143-149
  4. McNerney et al., Blood 2013;121(6):975-983
  5. Thoennissen et al., American J Haem 2011;86(8):699-701
  6. Arsham, MS., Barch, MJ. and Lawce HJ. (eds.) (2017) The AGT Cytogenetics Laboratory Manual. New Jersey: John Wiley & Sons Inc.
  7. Mascarello JT, Hirsch B, Kearney HM, et al. Section E9 of the American College of Medical Genetics technical standards and guidelines: fluorescence in situ hybridization. Genet Med. 2011;13(7):667-675.
  8. Wiktor AE, Dyke DLV, Stupca PJ, Ketterling RP, Thorland EC, Shearer BM, Fink SR, Stockero KJ, Majorowicz JR, Dewald GW. Preclinical validation of fluorescence in situ hybridization assays for clinical practice. Genetics in Medicine. 2006;8(1):16–23.

Microscope Images

Del 7q Deletion magnified
Area of Interest*
AML, MDS

Disclaimer

This product is intended to be used on Carnoy’s solution (3:1 methanol/acetic acid) fixed haematological samples.

*Disease information supported by the literature and is not a reflection of the intended purpose of this product.