HAEM5:Hairy cell leukaemia: Difference between revisions

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==Clinical Features==

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*Monocytopenia

*Lymphocytosis (low level)

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==Sites of Involvement==

*Liver

*Blood (small number)

==Morphologic Features==

==Immunophenotype==

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==Chromosomal Rearrangements (Gene Fusions)==

*Single case report of IGH-BRAF fusion positive, BRAF p.Val600Glu mutation negative HCL<ref name=":3" />

*Single case report of IGH-CCND1 fusion positive, BRAF p.Val600Glu mutation positive HCL<ref name=":4" />

*No consistent gene fusions

*Single case report of IGH-CCND1 fusion positive, BRAF p.Val600Glu mutation positive HCL<ref name=":4">{{Cite journal|last=Rahman|first=Zaid Abdel|last2=Muwalla|first2=Firas|last3=Jiang|first3=Liuyan|last4=Foran|first4=James|date=2020|title=Hairy cell leukemia with CCND1/IGH fusion gene and BRAF V600E mutation|url=https://www.ncbi.nlm.nih.gov/pubmed/32257795|journal=Leukemia Research Reports|volume=13|pages=100197|doi=10.1016/j.lrr.2020.100197|issn=2213-0489|pmc=7096740|pmid=32257795}}</ref>

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* Chromosomal Rearrangements (Gene Fusions)

* Individual Region Genomic Gain/Loss/LOH

* Characteristic Chromosomal Patterns

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!Alteration

<nowiki>*</nowiki>Not all BRAF mutations confer sensitivity to BRAF inhibitors, even if they are activating mutations<ref>{{Cite journal|last=Bracht|first=Jillian Wilhelmina Paulina|last2=Karachaliou|first2=Niki|last3=Bivona|first3=Trever|last4=Lanman|first4=Richard B.|last5=Faull|first5=Iris|last6=Nagy|first6=Rebecca J.|last7=Drozdowskyj|first7=Ana|last8=Berenguer|first8=Jordi|last9=Fernandez-Bruno|first9=Manuel|date=2019|title=BRAF Mutations Classes I, II, and III in NSCLC Patients Included in the SLLIP Trial: The Need for a New Pre-Clinical Treatment Rationale|url=https://www.ncbi.nlm.nih.gov/pubmed/31533235|journal=Cancers|volume=11|issue=9|doi=10.3390/cancers11091381|issn=2072-6694|pmc=6770188|pmid=31533235}}</ref>.

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

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*Recurrent gains and losses were found to be absent in HCLs from Chinese patients<ref>{{Cite journal|last=Zhang|first=Rui|last2=Wu|first2=Yongli|last3=Wang|first3=Xianfu|last4=Lu|first4=Xianglan|last5=Li|first5=Yan|last6=Li|first6=Shibo|last7=Yan|first7=Xiaojing|date=2020|title=Difference of genomic copy numbers alterations between hairy cell leukemia-variant and classical hairy cell leukemia: a pilot retrospective study in Chinese|url=https://www.ncbi.nlm.nih.gov/pubmed/32132867|journal=International Journal of Medical Sciences|volume=17|issue=3|pages=325–331|doi=10.7150/ijms.39307|issn=1449-1907|pmc=7053350|pmid=32132867}}</ref>

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==Characteristic Chromosomal Patterns==

IGHV4-34 (Immunoglobulin heavy chain variable segment) utilization is seen only in 10%<ref name=":0" /> of HCL but has predictive and prognostic implications<ref name=":7" />.

*IGHV4-34 (Immunoglobulin heavy chain variable segment) utilization is seen only in 10%<ref name=":0" /> of HCL but has predictive and prognostic implications<ref name=":7">{{Cite journal|last=Arons|first=Evgeny|last2=Kreitman|first2=Robert J.|date=2011|title=Molecular variant of hairy cell leukemia with poor prognosis|url=https://www.ncbi.nlm.nih.gov/pubmed/21599610|journal=Leukemia & Lymphoma|volume=52 Suppl 2|pages=99–102|doi=10.3109/10428194.2011.565841|issn=1029-2403|pmid=21599610}}</ref>.

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==Gene Mutations (SNV / INDEL)==

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*HCLs that utilize the IGVH4-34 segment lack BRAF p.Val600Glu mutations<ref name=":10">{{Cite journal|last=Xi|first=Liqiang|last2=Arons|first2=Evgeny|last3=Navarro|first3=Winnifred|last4=Calvo|first4=Katherine R.|last5=Stetler-Stevenson|first5=Maryalice|last6=Raffeld|first6=Mark|last7=Kreitman|first7=Robert J.|date=2012|title=Both variant and IGHV4-34-expressing hairy cell leukemia lack the BRAF V600E mutation|url=https://www.ncbi.nlm.nih.gov/pubmed/22210875|journal=Blood|volume=119|issue=14|pages=3330–3332|doi=10.1182/blood-2011-09-379339|issn=1528-0020|pmc=3321859|pmid=22210875}}</ref> and instead harbor MAP2K1 mutations in most cases<ref name=":11">{{Cite journal|last=Waterfall|first=Joshua J.|last2=Arons|first2=Evgeny|last3=Walker|first3=Robert L.|last4=Pineda|first4=Marbin|last5=Roth|first5=Laura|last6=Killian|first6=J. Keith|last7=Abaan|first7=Ogan D.|last8=Davis|first8=Sean R.|last9=Kreitman|first9=Robert J.|date=2014|title=High prevalence of MAP2K1 mutations in variant and IGHV4-34-expressing hairy-cell leukemias|url=https://www.ncbi.nlm.nih.gov/pubmed/24241536|journal=Nature Genetics|volume=46|issue=1|pages=8–10|doi=10.1038/ng.2828|issn=1546-1718|pmc=3905739|pmid=24241536}}</ref>

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==Epigenomic Alterations==

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!Molecular feature

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==Genetic Diagnostic Testing Methods==