HAEM5:Chronic eosinophilic leukaemia: Difference between revisions

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==WHO Classification of Disease==

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No single or specific genetic abnormality has been identified in CEL, NOS. Rearrangement of PDGFRA, PDGFRB, or FGFR1 excludes the diagnosis of CEL, NOS. PCM1-JAK2, ETV6-JAK2, or BCR-JAK2 are also specifically excluded. [1] Three unique cases of myeloid/lymphoid neoplasm with eosinophilia have shown ''FLT3'' rearrangement: one with t(13;14)(q12;q32)/''TRIP11-FLT3'' rearrangement, and two with ''ETV6-FLT3''. Eosinophilia and ''FLT3'' rearrangement typically shows myeloproliferative neoplasms, most frequently CEL, NOS, and T-ALL. [5] A unique case of CEL,NOS with a novel fusion gene between exon 22 of GCC2 and exon 12 of PDGFRB was detected and confirmed by PCR in a 54 year old man presenting with cough and dyspnea. [6]  

* Chromosomal Rearrangements (Gene Fusions)

* Individual Region Genomic Gain/Loss/LOH

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A recurrent karyotypic abnormality typically observed in myeloid disorders such as gain of chromosome 8, loss of chromosome 7 or isochromosome 17q supports a diagnosis as well as the presence of a translocation. [1] [1] Morsia et al demonstrated cytogenetic abnormalities in 15 of 17 (88.2%) patients diagnosed with CEL, NOS including trisomy 8 (n = 4), and complex karyotype (n = 3). [4]  

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|}Note: A more extensive list of mutations can be found in [https://www.cbioportal.org/ <u>cBioportal</u>], [https://cancer.sanger.ac.uk/cosmic <u>COSMIC</u>], and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

JAK2 mutations have been identified, however mutations in ASXL1, TET2 and EZH2 appear to be common. [1] The study by Morsia et al. of 17 CEL patients demonstrated two patients each with 13q, 20q deletion, and chromosome 1 abnormalities, one patient with monosomy 7 and one with 3q deletion. All seven patients with NGS studies harbored one or more mutations; ''ASXL1'' (42.9%); ''IDH1'' (28.6%), and one each (14.3%) with ''TP53'', ''SRSF2'', ''SH2B3'', ''STAT5B'', ''KDM6A'' and ''NF1'' mutations. [4] A novel ''JAK2'' exon 13 insertion/deletion mutant has been identified and described by Patel et al. in a patient fulfilling diagnostic criteria for both PV and CEL. This study demonstrated that JAK2ex13InDel bears mechanistic resemblance to JAK2V617F but can activate STAT5 in the absence of βc family cytokines IL-3, IL-5, and GM-CSF, potentially promoting eosinophilic differentiation. [7] Keleman et al. discussed STAT5B mutations as reported in four cases: two cases of CEL, NOS; one case of CMML with eosinophilia; and one case of MDS with eosinophilia, respectively. While the presence of a STAT5B N642H mutation may be a potential marker of chronic eosinophilic neoplasms, similar mutations have been described in nonclonal HE and may not be independently sufficient to establish a diagnosis of CEL, NOS. [8]  

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==References==

#Bain B.J, et al., (2017). Chronic eosinophilic leukemia, NOS, in World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues, Revised 4th edition. Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, Arber DA, Hasserjian RP, Le Beau MM, Orazi A, and Siebert R, Editors. IARC Press: Lyon, France, p54-56

#Ricci, F., Balducci, S., Guerrini, F., Grassi, S., Ciabatti, E., Baratè, C., . . . Galimberti, S. (2020). Sorafenib Induced Complete Cytogenetic and Molecular Response in a Chronic Eosinophilic Leukemia Case with t(12;13) Translocation. ''Clinical Hematology International,'' ''2''. doi:10.2991/chi.k.200714.001

          

<nowiki>*</nowiki>''Citation of this Page'': “Chronic eosinophilic leukaemia”. Compendium of Cancer Genome Aberrations (CCGA), Cancer Genomics Consortium (CGC), updated {{REVISIONMONTH}}/{{REVISIONDAY}}/{{REVISIONYEAR}}, <nowiki>https://ccga.io/index.php/HAEM5:Chronic_eosinophilic_leukaemia</nowiki>.