HAEM5:Myeloproliferative neoplasm, NOS: Difference between revisions

The clinical features are similar to other MPNs and reflect the stage of disease<ref name=":0" />. The early stage can variably show thrombocytosis and leukocytosis with or without anemia and minimal to absent organomegaly. Splanchnic vein thrombosis may be present<ref>{{Cite journal|last=Gianelli|first=Umberto|last2=Iurlo|first2=Alessandra|last3=Cattaneo|first3=Daniele|last4=Bossi|first4=Anna|last5=Cortinovis|first5=Ivan|last6=Augello|first6=Claudia|last7=Moro|first7=Alessia|last8=Savi|first8=Federica|last9=Castelli|first9=Roberto|date=2015-05|title=Discrepancies between bone marrow histopathology and clinical phenotype in BCR-ABL1-negative myeloproliferative neoplasms associated with splanchnic vein thrombosis|url=https://pubmed.ncbi.nlm.nih.gov/25840747|journal=Leukemia Research|volume=39|issue=5|pages=525–529|doi=10.1016/j.leukres.2015.03.009|issn=1873-5835|pmid=25840747}}</ref>. Marked splenomegaly and/or hepatomegaly with cytopenias can be present with advanced disease.

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==Sites of Involvement==

There is no defining immunophenotype.

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==Chromosomal Rearrangements (Gene Fusions)==

There are no associated chromosomal rearrangements. There should be no ''BCR''-''ABL1'' or ''PCM1-JAK2'' fusion and no ''PDGFRA'', ''PDGFRB'', or ''FGFR1'' rearrangement. Rearrangements that have been reported include t(4;12)(q12;p13)<ref name=":5">{{Cite journal|last=Zhang|first=Ling|last2=Wang|first2=Man|last3=Wang|first3=Zheng|last4=Zeng|first4=Zhao|last5=Wen|first5=Lijun|last6=Xu|first6=Yi|last7=Yao|first7=Li|last8=Cen|first8=Jiannong|last9=Li|first9=Hongzhi|date=2020-10|title=Identification of a novel ETV6 truncated fusion gene in myeloproliferative neoplasm, unclassifiable with t(4;12)(q12;p13)|url=https://pubmed.ncbi.nlm.nih.gov/32734549|journal=Annals of Hematology|volume=99|issue=10|pages=2445–2447|doi=10.1007/s00277-020-04207-y|issn=1432-0584|pmid=32734549}}</ref>.

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* Individual Region Genomic Gain/Loss/LOH

* Characteristic Chromosomal Patterns

Follow-up studies on a 6 - 12 month interval can provide additional information for classification<ref name=":0" />.

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==Individual Region Genomic Gain / Loss / LOH==

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There are no characteristic genomic gain/loss/LOH.

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==Characteristic Chromosomal Patterns==

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There are no characteristic chromosomal aberrations/patterns. Cytogenetic abnormalities have been described in four (5.6%) of 71 2008 WHO diagnosed cases<ref name=":1" /> and one (20%) of five 2016 WHO diagnosed cases<ref name=":3" />. Chromosomal aberrations that have been reported include trisomy 8<ref name=":1" /> and 46,XY,inv(12)(q15q24.1)<ref name=":3" />.

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==Gene Mutations (SNV / INDEL)==

Mutations in ''JAK2'', ''MPL'', and ''CALR'' are recurrent. A subset of cases have been reported to be negative for mutations in these three genes (i.e. triple negative). Limited studies have reported mutations in other genes including ''ASXL1''<ref name=":3" /> and ''ZRSR2''<ref name=":3" /><ref name=":5" />.

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==Epigenomic Alterations==

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Mutations in ''JAK2'', ''CALR'', and ''MPL'' lead to constitutive activation of the Janus kinase/signal transducer and activator of transcription (JAK-STAT) pathway. ''JAK2'' V617F mutations affect signalling through the EPOR, MPL, and G-CSFR homodimeric receptors while ''CALR'' and ''MPL'' mutations affect signalling through MPL only<ref>{{Cite journal|last=Vainchenker|first=William|last2=Kralovics|first2=Robert|date=02 09, 2017|title=Genetic basis and molecular pathophysiology of classical myeloproliferative neoplasms|url=https://pubmed.ncbi.nlm.nih.gov/28028029|journal=Blood|volume=129|issue=6|pages=667–679|doi=10.1182/blood-2016-10-695940|issn=1528-0020|pmid=28028029}}</ref>.

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==Genetic Diagnostic Testing Methods==